These easy lemon bars (or lemon slices) consist of a delicious shortbread crust topped with a very more-ish lemon filling that will keep you coming back for more.
I love lemon desserts. There is something just really nice about the super fresh taste of lemon in a dessert. When I was perfecting my easy lemon slice recipe, I knew I would start with my go-to whipped shortbread for a buttery shortbread crust. Then I experimented a bit with the amount of sugar in the lemon filling to create the best lemon bars ever.
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History
This delicious lemon dessert was invented in the USA in the 1960s. Lemon bars are also known as lemon squares, or as a lemon slice. This dessert bar typically consists of a shortbread crust that is tipped with a lemon curd filling.
Why You Will Love This Lemon Slice
- This is a super easy lemon bars recipe that is the perfect combination of simple shortbread crust and tart lemon filling.
- The secret to classic lemon bars is to use fresh lemon juice and lemon zest - which is exactly what this easy recipe calls for.
- The smooth baked lemon curd in this slice will instantly remind you of your favorite lemon meringue pie...but without the meringue.
- It's such a great make-ahead dessert...this slice freezes absolutely amazingly and can be stored for up to 3 months in the freezer!
- Plus it gets better when allowed to set in the fridge overnight.
- All you need are a few simple ingredients to make a really good lemon bar.
Ingredients
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.
NOTE - this shortbread base recipe is almost identical to the one used in my chocolate caramel slice or Millionaire's shortbread. Many other recipes use melted butter, however, I prefer the outcome of using softened butter instead.
Plain flour (all-purpose flour/standard grade flour) refers to flour that has a protein content of approximately 9.5-12%. If measuring by cups and not grams it is important to first fluff the flour in the container before spooning it into a cup and leveling it off with the back of a knife. This is one of the primary ingredients in the shortbread and is also used in the filling to help it thicken up.
White sugar (granulated or caster sugar) adds sweetness without really impacting additional flavors in baked goods. In this case, it sweetens the shortbread base as well as the lemon filling and allows the lemon flavor to really shine through.
NOTE - I decreased the amount of sugar in my go-to lemon slice recipe for the topping from 300g to 250g (I think this slight decrease is the perfect amount of sugar). If you like things on the sweeter side, you can definitely up the sugar factor to 300g.
Icing sugar (powdered or confectioners' sugar) is a finely ground sugar that typically contains between 2 and 5% of starch (such as tapioca or corn). This is used in the shortbread base to add a bit of snappiness, and then for decorating the lemon bars.
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.
Fresh lemons provide both the lemon zest and the lemon juice for the lemon mixture. The juice of two lemons is approximately ½ cup or 120mL, however, if your lemons are small you may need a little additional lemon juice for a top-up.
Eggs - I use a New Zealand size 6 egg, which is around the same size as Australian and South African Large Eggs, but closer to a US/Europe Medium sized egg.
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.
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 240mL/8 fl oz, tablespoons are 15mL and teaspoons are 5mL.
Step-by-Step Instructions
1 - Preheat the oven to 180°C/350F. Grease and line a 9-inch square cake pan (23cm square) with parchment paper (making sure the baking paper hangs over the sides of the pan to allow for easy removal once the slice has cooled).
2- In a large bowl, add the softened butter, caster, icing sugar, and salt (if using unsalted butter). Cream using a whisk until soft and well-combined.
Note - It can be quite cold in my kitchen (especially during winter) and sometimes I have to zap the butter after the addition of the cold sugar to get it back to the correct soft texture.
3 - Add in the flour and salt and mix with a spoon until a soft pliable dough is formed. Then knead the dough a few times by hand to ensure the dough is fully incorporated.
4 - Press the shortbread crust mixture into the prepared pan. Then use the back of a measuring cup and press the dough firmly into the pan. Prick the dough with a fork throughout and bake for 20 minutes until the base is just slightly golden brown.
5 - While the base is baking, make the lemon bar filling. Place the sugar and lemon zest in a large mixing bowl, or the bowl of a stand mixer. Begin by rubbing the lemon zest into the sugar.
Note - The zest can be rubbed into the sugar using a stand mixer or electric mixer but beaten together for a minute or two at medium speed.
6 - Then add in the flour, and mix through. Then add in the eggs and lemon juice. Beat together for 2-3 minutes.
7 - When the biscuit base is golden brown it is done. Then pour the lemon filling on top of the baked crust and bake for a further 20 minutes or until the middle just has the slightest jiggling.
8 - Turn off the oven, and prop it open with a wooden spoon, allowing the lemon squares to cool slowly in the oven for an hour. Remove from the oven and allow to cool to room temperature before transferring to the fridge for at least 2 hours or overnight.
Note - Allowing the lemon slice to cool slowly reduces the chances of the lemon filling cracking. However, a few cracks in the top do not take away how delicious these lemon bars are.
9 - Lift the slice out of the cake pan, and place it on a cutting board. Use a sharp clean knife for clean slices and cut into 20-25 squares. Decorate with a generous dusting of icing or powdered sugar.
Other Bars/Slices You May Like
Storage and Freezing
This lemon slice can be stored in the fridge in an airtight container for up to a week, or frozen for up to 3 months.
To freeze, slice into individual portions, then wrap in cling film/plastic wrap and aluminum foil before placing into an airtight container. To defrost, unwrap and allow the slice to thaw in the fridge before serving.
Lemon Bars/Lemon Slice FAQ
To get clean even slices, mark your slice using a ruler, and then warm up your sharp knife in hot water, wipe dry, and cut. By warming up the blade and wiping it clean in between each slice you will get perfect slices.
The lemon slice should be cut once the lemon slice has been allowed to cool and set in the fridge for at least two hours.
Lemon bars can be stored in the fridge for up to a week, or up to 3 months when frozen.
Yes! These lemon bars are best made the day before and allowed to chill in the fridge overnight. However, the slice can also be made and frozen a few months (3 months) ahead of an event.
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📖 Recipe
Lemon Slice/Lemon Bars
Ingredients
Shortbread Base
- ¾ cup butter (softened)*Note 1
- ½ cup white granulated sugar (caster/granulated)
- ½ cup icing sugar (powdered/confectioner's sugar)
- 2 cups plain flour (all-purpose/standard grade)
- ½ teaspoon salt (if using unsalted butter)
Lemon Curd Filling
- 4 eggs (medium/large/size 6)
- 1¼ cups white granulated sugar (caster/granulated)
- 4 tablespoons plain flour (all-purpose/standard grade)
- zest of 2 lemons
- ½ cup lemon juice (100-125 mL or juice of 2 lemons)
Icing Sugar Sprinkle
- 2 tablespoons icing sugar (powdered/confectioner's sugar)
Instructions
- Preheat the oven to 180°C/350F. Grease and line a 9-inch square cake pan (23cm square) with parchment paper (making sure the baking paper hangs over the sides of the pan to allow for easy removal once the slice has cooled).
- In a large bowl, add the softened butter, caster, icing sugar, and salt (if using unsalted butter). Cream using a whisk until soft and well-combined. (*Note 5)¾ cup butter, ½ cup white granulated sugar, ½ cup icing sugar
- Add in the flour and salt and mix with a spoon until a soft pliable dough is formed. Then knead the dough a few times by hand to ensure the dough is fully incorporated.2 cups plain flour, ½ teaspoon salt
- Press the shortbread crust mixture into the prepared pan. Then use the back of a measuring cup and press the dough firmly into the pan. Prick the dough with a fork throughout and bake for 20 minutes until the base is just slightly golden brown.
- While the base is baking, make the lemon bar filling. Place the sugar and lemon zest in a large mixing bowl, or the bowl of a stand mixer. Begin by rubbing the lemon zest into the sugar (*Note 6).
- Then add in the flour, and mix through. Then add in the eggs and lemon juice. Beat together for 2-3 minutes.4 eggs, 1¼ cups white granulated sugar, 4 tablespoons plain flour, zest of 2 lemons, ½ cup lemon juice
- When the biscuit base is golden brown it is done. Then pour the lemon filling on top of the baked crust and bake for a further 20 minutes or until the middle just has the slightest jiggling.
- Turn off the oven, and prop it open with a wooden spoon, allowing the lemon squares to cool slowly in the oven for an hour. Remove from the oven and allow to cool to room temperature before transferring to the fridge for at least 2 hours or overnight. (*Note 7)
- Lift the slice out of the cake pan, and place it on a cutting board. Use a sharp clean knife for clean slices and cut into 20-25 squares. Decorate with a sprinkling of icing or powdered sugar.
Video
Notes
- For butter: 1 cup of butter = 225 grams (which is 2 sticks of butter), and slightly less than a metric cup. Many slice recipes use melted butter, but I prefer the outcome when using softened butter.
- I decreased the amount of sugar in my go-to lemon slice recipe for the topping from 300g to 250g. If you like things on the sweeter side, you can definitely up the sugar factor to 300g.
- New Zealand size 6 eggs are around the same size as an Australian/South African Large or a US/Europe Medium.
- Fresh lemons are a must for a good lemon bar. This recipe requires ½ cup (120mL) of lemon juice, which is approximately the amount of juice that can be squeezed out of two large lemons. If your lemons are small, then you may need an additional lemon or two. To zest a lemon you can use a zesting tool or a microplane/fine grater.
- It can be quite cold in my kitchen (especially during winter) and sometimes I have to zap the butter in the microwave after the addition of the cold sugar to get it back to the correct soft texture.
- The zest can be rubbed into the sugar using a stand mixer or electric mixer but beaten together for a minute or two at medium speed.
- Allowing the lemon slice to cool slowly reduces the chances of the lemon filling cracking. However, a few cracks in the top do not take away how delicious these lemon bars are.
STORAGE AND FREEZING
This lemon slice can be stored in the fridge in an airtight container for up to a week, or frozen for up to 3 months. To freeze, slice into individual portions, then wrap in cling film/plastic wrap and aluminum foil before placing into an airtight container. To defrost, unwrap and allow the slice to thaw in the fridge before serving.Nutrition
Nutrition information is an estimate. If scaling the recipe remember to scale your cook and bakeware accordingly. As an Amazon Associate and member of other affiliate programs,I earn from qualifying purchases.
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