A tan slice or tan square is a super tasty caramel shortbread crumble bar. This classic New Zealand treat consists of a caramel filling sandwiched with a delicious simple buttery shortbread.
A tan slice or tan square is simply a caramel shortbread bar. This means that caramel filling made with sweetened condensed milk is poured over a shortbread base, with additional shortbread crumbled over the top before it is baked.
Some variations I've seen around New Zealand include having chocolate chips sprinkled over the crumbled shortbread.
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Recipe Development Notes
The first time I had a tan slice here in New Zealand, I was like...I can do that better (granted it was a tan slice from the local supermarket so it wasn't gourmet or bakery quality).
However, it immediately reminded me of my caramel slice or Millionaire's Shortbread and my Jam Squares. So I knew I was halfway there.
I did make a few changes to the recipes used, mostly so that it would be easier for my readers to convert between grams and cups/tablespoons for the caramel filling. So with a few tweaks, and tests here and there, I perfected my tan slice or tan square recipe.
Why This Recipe Works
- It's a super easy recipe that comes together with a few ingredients.
- This is an egg-free recipe.
- The buttery shortbread is really complimented by the rich caramel filling.
- This New Zealand classic is a treat that goes down really well!
Ingredients
Here are some notes on the ingredients used in this recipe. Please see the recipe card for quantities.
Butter adds flavor, softness, and moisture and sometimes aids in the leavening of baked goods. I use New Zealand butter in my recipes, which has approximately 82% butterfat and can be very yellow (similar to European or Irish butter). Butter cannot be substituted with butter or margarine spreads, but it can be substituted with baking margarine. Butter is a key ingredient in the whipped shortbread base. The butter must be at room temperature for this recipe.
Salt is a crucial ingredient in all baked goods. I use table salt in all my recipes. One teaspoon of table salt equals 1.5 teaspoons of Morton Kosher Salt equals 2 teaspoons of Diamond Crystal.
Flour - plain, standard grade, or all-purpose flour is what this recipe calls for.
Icing Sugar or Powdered Sugar adds sweetness with the added starches giving the biscuit a tender snap.
Plain white or caster sugar gives a crispness to this biscuit that is otherwise completely lost with just using icing sugar.
Brown sugar - this is a caramel filling after all and needs sugar to form a delightful caramel in the end. You can use light brown sugar or dark brown sugar for these caramel shortbread bars.
Full cream sweetened condensed milk adds sweetness and creaminess. Do not use a low-fat version as the fat in the condensed milk is necessary for the caramel to thicken and set up.
Golden Syrup adds flavor and keeps the caramel soft, even though it sets enough to be sliced. Golden syrup can be substituted with maple syrup, honey or corn syrup.
Weighing & Measuring Ingredients
Weighing ingredients with a kitchen scale is more accurate than using measuring cups. All my recipes are developed and tested using grams only.
However, I have activated the metric-to-cup conversions. Simply click on "cups" or "metric" for your preferred measurements. For these conversions, cups are equal to 240 millilitres/8 fluid ounces, tablespoons are 15 milliliters and teaspoons are 5mL.
Step-by-Step Instructions
Step 1 - Preheat the oven to 180°C/355°F. Grease and line a 9"x9" square cake tin, making sure that the baking paper comes up the sides to allow for easy removal and to prevent the caramel from sticking to the sides.
Step 2 - Combine the butter, icing sugar, white sugar, and vanilla in a large mixing bowl. Beat together until the butter and sugars are well incorporated, light, and fluffy and the butter has lightened in color.
Step 3 - Add in the flour and salt, mixing with a spatula or wooden spoon until a soft pliable dough forms.
Step 4 - Divide the dough into thirds. Press ⅔ of the dough into the bottom of the prepared tin. Use the back of a cup measurer or offset spatula to really press the dough into the pan. Prick the dough with a fork throughout and bake for 15 minutes until the biscuit base is a nice light golden brown.
Step 5 - Allow the biscuit base to cool slightly in the tin while making the caramel filling.
Step 6 - Place the butter, syrup, sugar, and condensed milk in a medium-sized saucepan and bring to a boil, stirring the entire time all the ingredients are melting together. Once the caramel has started to heat up and boil, whisk/stir constantly for 5 to 10 minutes until the caramel thickens and browns. To test the caramel, take a cold teaspoon or knife and dip it in, if it sets up fairly quickly the caramel is done. Take off the heat and stir through the salt and vanilla.
Step 7 - Pour the caramel filling over the biscuit base, and smooth it out with a spatula if needed. Then crumble the last ⅓ of the shortbread over the caramel filling. Bake for a further 15 minutes at 180°C/355°F.
Step 8 - Once baked, allow the slice to cool completely before slicing, this can take between 2 to 3 hours at room temperature.
Step 9 - Once the slice has cooled completely. Remove the slice from the tin, and slice with a sharp knife.
Expert Tips for this Recipe
- Use room-temperature ingredients for the shortbread base.
- Have a cold spoon or knife ready to test the caramel (you don't want to be running around looking for this when you have hot caramel on the stovetop).
- Make sure your oven is properly preheated before baking - this tan slice doesn't have a very long baking time, and if your oven is not properly preheated (or runs a bit cool) then it may need a bit longer to fully bake.
- Allow the tan slice to cool completely before cutting it into tan squares.
- Use a sharp knife that has been heated up with warm water and dried before slicing.
- Clean the knife before each slice for those super sharp edges.
How do I know when the caramel is finished cooking?
I use the simple method of a cold (meaning that it has been unused and isn't warmed up by the hand) spoon or butter knife. I then dip it into the caramel if the caramel is cooked, it will set fairly quickly and not drip off the utensil.
Why do you bake the base before adding the caramel?
I like to give my base a head start, to make sure that the shortbread is baked before popping it in for another 15 minutes with the caramel and shortbread crumble. I use this method in my Caramel Slice or Millionaire's Shortbread and think it works quite well.
Ovens & Air Fryers
The temperatures stated are for conventional ovens. For convection, fan-forced, fan-assisted, or air-fryers, the temperature must be reduced by 20°C/25°F.
For baking, make sure the oven is fully preheated, and that the rack is in the middle of the oven. Open the oven as little as possible. For best baking results use an oven thermometer.
Remember that all ovens work slightly differently and bake times may need to be adjusted for your specific oven.
Small Batch
If you only want to make a small batch - I recommend halving the recipe and baking this delicious caramel tan slice in a loaf pan.
Storage and Freezing
Store this tan slice in an airtight container for up to a week. Or freeze for up to 3 months.
This tan slice can be frozen for up to 3 months and brought to room temperature before serving. Before freezing, make sure to slice into the desired portions. Wrap each slice separately in cling film or plastic wrap and then with foil. Alternatively, the slices can be stored in an airtight container, but I would place a layer of baking paper between the slices to stop them from sticking to each other.
Tan Slice FAQ
Yes! The slices or squares can be wrapped and frozen individually, or in an airtight container separated by pieces of baking paper.
I used a 9"x9" square cake tin for this recipe. However, you can get away with an 8"x8", keep in mind that the layers will be thicker.
In Australia and New Zealand, cafes and bakeries sell "slices" which can range from tray cakes or sheet cakes to cookie bars. They can be baked or unbaked, but are usually assembled in rectangular or square cake pans, and sliced into squares or rectangles for sharing.
Other Kiwi Recipes You May Like
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Recipe Card
Tan Slice
Equipment
- 1 9x9 Inch (23x23cm) Square Cake Pan
Ingredients
Whipped Shortbread Base
- 225 grams butter (soft but not melted*note 1)
- 60 grams icing sugar (powdered/confectioner's)
- 100 grams white granulated sugar (caster/granulated)
- 1 teaspoon vanilla extract
- 330 grams plain flour (all-purpose flour/standard grade)
- ½ teaspoon table salt
Caramel Filling
- 115 grams butter (*Note 2)
- 110 grams light brown sugar
- 1 tin/can sweetened condensed milk (397grams/14oz.)
- 40 grams golden syrup (maple syrup)
- ¾ - 2 teaspoons sea salt (add to taste)
- 1 teaspoon vanilla extract
Instructions
- Preheat the oven to 180°C/355°F. Grease and line a 9"x9" square cake tin, making sure that the baking paper comes up the sides to allow for easy removal and to prevent the caramel from sticking to the sides.
- Combine the butter, icing sugar, white sugar and vanilla in a large mixing bowl. Beat together until the butter and sugars are well incorporated, light, fluffy and the butter has lightened in colour.225 grams butter, 60 grams icing sugar, 100 grams white granulated sugar, 1 teaspoon vanilla extract
- Add in the flour and salt, mixing with a spatula or wooden spoon until a soft pliable dough forms.330 grams plain flour, ½ teaspoon table salt
- Divide the dough into thirds. Press ⅔ of the dough into the bottom of the prepared tin. Use the back of a cup measurer or offset spatula to really press the dough into the pan. Prick the dough with a fork throughout and bake for 15 minutes until the biscuit base is a nice light golden brown.
- Allow the biscuit base to cool slightly in the tin while making the caramel filling.
- Place the butter, syrup, sugar, and condensed milk in a medium-sized saucepan and bring to a boil, stirring the entire time all the ingredients are melting together. Once the caramel has started to heat up and boil, whisk/stir constantly for 5 to 10 minutes until the caramel thickens and browns. To test the caramel, take a cold teaspoon or knife and dip it in, if it sets up fairly quickly the caramel is done. Take off the heat and stir through the salt and vanilla.115 grams butter, 110 grams light brown sugar, 1 tin/can sweetened condensed milk, 40 grams golden syrup, ¾ - 2 teaspoons sea salt, 1 teaspoon vanilla extract
- Pour the caramel filling over the biscuit base, and smooth out with a spatula if needed. Then crumble the last ⅓ of the shortbread over the caramel filling. Bake for a further 15 minutes at 180°C/355°F.
- Once baked, allow the slice to cool completely before slicing, this can take between 2 to 3 hours at room temperature.
- Once the slice has cooled completely. Remove the slice from the tin, and slice with a sharp knife.
Notes
- 225 grams = 2 sticks = 1 cup of butter. While 225 grams of butter = US cup, it is less than a metric cup of butter.
- 115 grams = 8 tablespoons = 1 stick (which is half a US cup, and less than half a metric cup of cutter)
Storage and Freezing
Store this tan slice in an airtight container for up to a week. Or freeze for up to 3 months.Nutrition
Nutrition information is an estimate. If scaling the recipe remember to scale your cook and bakeware accordingly. All temperatures stated are conventional, unless otherwise stated. Recipes tested in grams and at sea level.
Kate says
My butter separated from the caramel during cooking, what did I do wrong?
Mary-Lou Watkins says
Hi,
Sorry your caramel split. I have never had this issue before. So I did some reading and it seems like there can be a number of reasons for the butter splitting out. It can result from having uneven heating on the element, heating the mixture too quickly or cooling it down too quickly, not stirring constantly, using a thin bottomed saucepan/pot, and even high humidity can cause it to occur.
Michelle says
Love it! This is my second time making it, but I almost completely cut the salt out of the caramel in the second one, first one was way to salty with 2tsp of salt
Mary-Lou says
Thank you so much for the feedback! I'm going to add a sliding scale to the salt in the recipe, thank you.
Jen says
Delicious, wasn't sure which brown sugar to use so tried light brown and it was great, will try dark soft brown next time. My partner loves it.
Mary-Lou says
Hi, thank you!
I generally use light brown sugar but I'm going to update the recipe to reflect that.
ML
Line Fick says
Loved the recipe thank you! I cheated and used canned caramel, but the shortbread was so yum!
Mary-Lou says
Thank you so much! And I wholeheartedly love the idea of using canned caramel 🙂
Monika says
Hi! Great recipe from the looks of it. I will try it! Can I use HONEY in place of golden syrup? I don't know what that is...don't have it - but always have honey! Thanks.
Mary-Lou says
Hi,
Honey will work just fine, it may just have a honey flavor. Other syrups that can be used include maple or corn syrup. I'm going to add that to the substitutions, thank you for reminding me about honey and that golden syrup (basically a light treacle) is a very common ingredient in the UK, Australia, New Zealand and South Africa (probably around the commonwealth) but not as well-known in North America.
Happy Baking!