Lemon Bars

The recipe, step by step

When life gives you lemons, you make lemon bars. These are surprisingly simple to prepare, with a buttery shortbread biscuit base and a silky lemon filling that has just the right balance of sweetness and sharp citrus flavour.

I played with this recipe until I got exactly the result I wanted. The shortbread base is rich and crumbly without being overly sweet, which makes it the perfect partner for that bright lemon layer.

I use both fresh lemon juice and zest because the zest gives the filling an extra zing. For a slightly gentler lemon flavour, simply reduce or leave out some of the zest while keeping the lemon juice in the recipe.

Once baked, the bars need a good 2-hour chill before slicing. That time in the fridge helps the filling set properly and gives you those lovely clean layers when you cut into them.

For more citrus baking, try my Moreish Lemon Biscuits or these wonderfully soft and chewy Lemon Crinkle Cookies.

Recipe Highlights

• Easy: A straightforward shortbread base topped with a simple whisked lemon filling.
• Taste: Bright, tangy lemon balanced by a sweet, buttery biscuit base.
• Texture: Crisp, crumbly shortbread underneath a smooth and silky lemon layer.
• Make ahead: The bars need at least 2 hours in the fridge and can also be chilled overnight.
• Quantity: Makes 16 lemon bars in a 20 × 20 cm (8 × 8 inch) baking tin.
• Preparation: 20 minutes.
• Baking: 30–35 minutes in total: 10 minutes for the shortbread base, followed by 20–25 minutes for the lemon filling.
• Chilling: 2 hours.
• Total time: Allow approximately 3 hours, including cooling and chilling.

Ingredients and Substitutions

Shortbread Biscuit Base

• Butter: Use 125 g butter. Butter is the main flavour in the shortbread, so I recommend using a good-quality butter.
• Caster sugar: Use 50 g caster sugar. It gives the shortbread just enough sweetness without overpowering the lemon filling.
• Fine sea salt: Use a pinch. I highly recommend keeping the salt in the base because it balances the sweetness and enhances the butter and vanilla flavours.
• Vanilla: Use ½ teaspoon pure vanilla extract or ¼ teaspoon vanilla paste. The vanilla rounds out the flavour of the shortbread beautifully without competing with the lemon.
• Plain flour: Use 180 g plain or all-purpose flour. This gives the base its tender, crumbly shortbread texture.

Lemon Filling

• Medium eggs: Use 4 medium eggs, approximately 200 g in total. The eggs give the lemon filling its smooth, custard-like structure.
• Caster sugar: Use 375 g caster sugar. Although this sounds generous, it balances the acidity of the lemon while also contributing to the texture and structure of the filling.
• Lemons: Use 2 organic or unwaxed lemons, giving approximately 150 ml freshly squeezed lemon juice plus the zest. I strongly recommend using fresh lemon juice rather than bottled juice for the brightest, cleanest flavour.
• Plain flour: Use 45 g plain or all-purpose flour. This helps the lemon layer set cleanly while keeping its silky texture.
• Fine sea salt: Use a pinch. A little salt balances the sweetness and makes the lemon flavour taste even brighter.

Decoration

• Icing sugar: Use 3 tablespoons icing sugar to generously dust the chilled bars before serving.

How to Make Lemon Bars

1. Preheat the oven: Preheat the oven to 200°C / 180°C fan / 400°F / Gas 6.

2. Prepare the baking tin: Line a 20 × 20 cm (8 × 8 inch) baking tin with baking parchment. I like to leave enough parchment extending over the sides to make the finished bars easier to lift out.

3. Cream the butter and sugar: Place the butter and caster sugar in a medium mixing bowl or stand mixer and beat together until smooth and creamy.

4. Add the remaining shortbread ingredients: Add the vanilla and fine sea salt, then sift in the flour.

5. Bring the dough together: Continue mixing until the mixture begins to come together. It will still look slightly crumbly, which is exactly what you want for a tender shortbread base.

6. Press into the tin: Transfer the shortbread mixture to the prepared baking tin and press it firmly into an even layer.

7. Prick and pre-bake the shortbread: Use a fork to make a few holes across the surface, then bake for 10 minutes.

8. Make the lemon filling: While the shortbread is baking, place the eggs, caster sugar, fine sea salt, flour, lemon zest and 150 ml freshly squeezed lemon juice into a large bowl or measuring jug. Whisk until just combined. The mixture will be quite thin at this stage.

9. Pour over the shortbread: Once the biscuit base has baked for 10 minutes, carefully pour the lemon filling over it. You can either pull the oven shelf forward and pour the filling directly onto the base or briefly remove the tin from the oven.

10. Continue baking: Bake for a further 20–25 minutes, until the centre is slightly firm to the touch and no longer wobbles.

11. Cool: Remove the baking tin from the oven and allow the lemon bars to cool completely.

12. Chill: Transfer the cooled bars to the fridge for at least 2 hours, or leave them overnight, until the lemon filling is completely set.

13. Slice and decorate: Lift the chilled lemon bars from the tin, cut into 16 equal squares and dust generously with icing sugar just before serving.

Nigel’s Recipe Tips

Line the baking tin properly. I highly recommend using baking parchment and leaving some overhang at the sides. It makes removing the chilled bars considerably easier.

Use good-quality butter. Shortbread contains very few ingredients, so the flavour of the butter really does make a difference.

Use fresh lemon juice. I recommend freshly squeezed juice rather than bottled lemon juice. Fresh lemons give you a much brighter, cleaner citrus flavour.

Choose unwaxed lemons. As the zest goes directly into the filling, organic or unwaxed lemons are preferable.

Zest before juicing. It is much easier to zest a whole lemon than one you have already squeezed.

Don’t overmix the filling. Whisk only until everything is evenly combined. There is no need to incorporate lots of air.

Use a measuring jug for the filling. I like to mix the lemon filling in a large measuring jug because it makes pouring it over the hot shortbread base much easier.

Look for a set centre. After 20–25 minutes, the centre should be slightly firm and should no longer wobble when the tin is gently moved.

Don’t rush the chilling time. Give the bars the full 2 hours in the fridge before cutting. Overnight chilling is even better when you want particularly neat slices.

Use a clean knife for slicing. Wipe the blade between cuts to keep those distinct shortbread and lemon layers looking tidy.

Dust just before serving. Icing sugar gradually absorbs moisture from the lemon filling, so I prefer to add it shortly before the bars are served.

Variations

Lavender Lemon Bars

For a delicate floral flavour, blend one-third of the filling sugar with 1 tablespoon culinary lavender in a food processor for 15–20 seconds.

Mix it back into the remaining sugar and continue with the lemon filling as usual.

Almond Shortbread

Add a few drops of almond essence while beating the butter and sugar together for the shortbread base.

Raspberry or Blueberry Lemon Bars

Prepare the lemon filling as usual.

Place 60 g raspberries or blueberries in a small bowl and lightly coat them with flour. This helps manage some of the additional moisture.

Gently add the fruit to the finished lemon filling before pouring it over the pre-baked shortbread.

Orange Bars

Replace the lemon juice and zest with orange for a sweeter and less acidic citrus version.

Pink Grapefruit Bars

Use pink grapefruit juice and zest instead of lemon for a more delicate citrus flavour with a subtle bittersweet edge.

Frequently Asked Questions

Why Do You Bake the Shortbread Base First?

Pre-baking the shortbread for 10 minutes allows it to begin setting before the liquid lemon filling is added.

This helps create two distinct layers rather than allowing the filling to soak directly into the raw biscuit mixture.

How Long Do Lemon Bars Bake?

The shortbread base bakes first for 10 minutes.

Once the lemon filling has been added, the bars return to the oven for a further 20–25 minutes.

That gives a total baking time of approximately 30–35 minutes.

Can I Reduce the Lemon Zest?

Yes. I use the zest because I love a pronounced lemon flavour, but you can reduce it or leave it out for something milder.

Keep the lemon juice in the recipe because it is an important part of the filling.

Can I Use Bottled Lemon Juice?

I recommend freshly squeezed lemon juice. It gives these bars a cleaner and brighter citrus flavour, particularly because we are also using fresh zest.

Why Is My Lemon Filling So Thin Before Baking?

That is completely normal.

The filling is quite liquid when it is poured onto the shortbread. The eggs and flour set it during baking, and it firms considerably more as it cools and chills.

How Do I Know When Lemon Bars Are Ready?

After 20–25 minutes of baking with the filling, the centre should feel slightly firm and should no longer visibly wobble.

Do not wait for the filling to become completely firm in the oven. It continues to set as it cools and again during chilling.

Why Do Lemon Bars Need to Be Chilled?

Chilling allows the lemon layer to set fully.

It also makes the bars much easier to lift from the tin and cut into clean, tidy squares.

Give them at least 2 hours, although chilling overnight works particularly well.

Can I Make Lemon Bars the Day Before?

Yes. In fact, these are ideal for preparing ahead.

Bake and cool them, refrigerate overnight, then slice and dust with icing sugar before serving.

Can I Use Other Citrus Fruits?

Yes. Orange and pink grapefruit both work well and will generally produce a gentler, less acidic flavour than lemon.

Tools You’ll Need

• 20 × 20 cm (8 × 8 inch) baking tin
• Baking parchment
• Medium mixing bowl or stand mixer
• Large mixing bowl or measuring jug
• Electric mixer
• Fine grater or zester
• Citrus juicer
• Fine sieve
• Whisk
• Rubber spatula
• Fork
• Sharp knife
• Digital kitchen scales

Storage and Freezing

Storing

These lemon bars are excellent for making ahead.

Once completely cooled and chilled, store them in an airtight container in the fridge for up to 5 days.

If you need to stack them, place a sheet of baking parchment between the layers to prevent them sticking together.

I recommend storing them without the final dusting of icing sugar because the sugar gradually absorbs moisture while refrigerated. Dust them shortly before serving instead.

Freezing

Lemon bars freeze well for up to 3 months.

For the easiest serving, chill the bars completely and cut them into individual portions before freezing.

Do not dust them with icing sugar beforehand.

Wrap each bar well in cling film or arrange them in a freezer-safe airtight container, placing baking parchment between layers.

Defrost the bars overnight in the fridge or allow them to come gradually to room temperature.

Once defrosted, dust with fresh icing sugar before serving.

Nutrition

Serving: 1 lemon bar (1/16 of the recipe)

Calories: 235.82 kcal · 12% DV
Total Fat: 7.73 g · 11% DV
Carbohydrates: 38.96 g · 15% DV
Sugars: 27.56 g · 31% DV
Protein: 3.19 g · 6% DV
Sodium: 27.79 mg · 1% DV
Fibre: 0.43 g · 2% DV

% Daily Values are based on a 2,000-calorie diet.

Nutritional information is provided as an estimate and may vary depending on the exact ingredients, brands and serving size used.

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