Tan Slice

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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.

Three tan squares stacked on each other to show the layers of shortbread and caramel.

Jump to:

What is a tan slice?
Why This Recipe Works
Ingredients
Step-by-Step Instructions
Expert Tips for this Recipe
Why do you bake the base before adding the caramel?
Storage and Freezing
Tan Slice FAQ
📖 Recipe
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What is a tan slice?

A tan slice or tan square is simply a caramel shortbread crumble bar. Meaning that caramel filling made with 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.

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 test here and there I perfected my tan slice or tan square recipe.

Why This Recipe Works

It's a really easy recipe that comes together with a few ingredients.
This is an egg-free recipe...which is great for the current egg shortage here in New Zealand.
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.

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.

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.

Room Temperature Ingredients

Use room-temperature ingredients! Using room temperature ingredients ensures that ingredients in the batter or dough will incorporate easier. Take note that room temperature refers to around 20°C/68F.

To bring eggs to room temperature quickly, place them into warm water for about 10 to 15 minutes.
To bring butter to room temperature quickly, cut the butter into cubes and zap it in the microwave at 20% power in 10-second intervals. Or place the cubes in a bowl over warm water (such as with a double boiler) over low heat for 1 minute!
Milk, buttermilk, and cream can be brought to room temperature by zapping in the microwave at 20% power in 10-second intervals. Or on low heat for a minute or two swirling every 10-15 seconds.
If the butter is too warm/soft for baking - pop it into the fridge for 20-30 minutes.

Weighing Ingredients

Weighing ingredients is more accurate than measuring cups overall, and this is my recommendation for my recipes as they are all developed and tested using grams only.

However, I have activated the grams-to-cup conversions on the recipe card. Simply click on "cups" underneath the ingredient list. For these conversions, cups are equal to 236mL/8 fluid ounces, tablespoons are 15mL and teaspoons are 5mL.

Measuring cups and spoons are an essential addition to every kitchen! Especially if you don't use a kitchen scale. Invest in a set to ensure you add the correct ingredients for accurate measuring. When in doubt - always use a level spoon or cup measure.

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 - creamed butter and sugars in a mixing bowl.

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 - soft pliable shortbread dough in a mixing bowl.

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 4 - shortbread dough divided into thirds in a mixing bowl.

Step 4 - dough pressed into cake tin and pricked with a fork.

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 7 - caramel poured over the shorbread base and topped with crumbled shortbread.

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.

Sliced tan slice set on it's side to show the defined layers of caramel and shortbread.

Expert Tips for this Recipe

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 cooked 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, or the gas mark by 1.

For baking, a general rule is to have the oven rack in the middle of the oven.

For best baking results invest in an oven thermometer, as the temperature dials on the oven may not be accurate. Place the thermometer in the middle of the center rack for the most accurate results. I hang my oven thermometer off the center of my oven rack.

Keep in mind that all ovens work slightly differently and bake times may need to be adjusted slightly for your specific oven.

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

Can a tan slice or tan square be frozen?

Yes! The slices or squares can be wrapped and frozen individually, or in an airtight container separated by pieces of baking paper.

What cake tin do you use?

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.

What are slices in Australia?

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.

Close up of a baked tan slice before being cut into squares.

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Tan Slice

What is a tan slice?

Why This Recipe Works