These lemon bars have a buttery shortbread base and a firm, tangy lemon filling that slices cleanly after a couple of hours in the fridge. The ingredient list is short, the steps are straightforward, and the result is reliably good — which is exactly why this recipe gets made again and again.
What makes this version work
Two things matter most here. First, you pre-bake the crust before adding the filling. Skipping that step leaves you with a soggy, underdone base that can’t support the lemon layer — 15 to 20 minutes in the oven until the edges are just golden is what gives the shortbread its structure. Second, the filling uses a small amount of flour alongside the eggs, sugar, and lemon juice. That flour is what helps the filling set firmly enough to cut into clean bars rather than collapsing into a wobbly mess. Neither step is complicated, but both are non-negotiable.
About the ingredients
- Lemon juice: Freshly squeezed is important here. Bottled lemon juice has a duller, slightly bitter flavor that shows up clearly in the finished bars. You’ll need roughly 4 to 5 medium lemons to get ⅔ cup of juice.
- Eggs: The eggs are doing real structural work in the filling, not just adding richness. Don’t reduce the quantity or swap in egg whites — the yolks are part of what gives the filling its set and color.
- Butter: Use unsalted so you control the salt level in the crust. The butter needs to be properly softened, not melted — melted butter changes the texture of the shortbread.
Mistakes to avoid
- Pouring filling onto a hot crust: Let the crust cool for at least 5 minutes before adding the lemon mixture. Pouring it onto a very hot crust can cause the bottom layer to puff or crack as the filling bakes.
- Cutting before fully chilled: The bars need the full 2 hours of refrigeration to firm up. Cutting them warm or even just room-temperature results in a filling that smears and sticks to the knife.
- Dusting powdered sugar too early: Add the powdered sugar right before serving, not before refrigerating. It absorbs into the filling overnight and disappears completely.
- Uneven crust thickness: Press the dough as evenly as you can across the pan — thin spots overbake and turn hard, while thick corners stay underdone. A flat-bottomed measuring cup works well for smoothing it out.
- Overmixing the filling: Whisk just until smooth. Beating too much air into the eggs can cause the surface of the filling to crack or bubble as it bakes.
Storage and reheating
Store the bars in an airtight container in the fridge for up to 5 days — they actually taste better on day two once the filling has fully set and the flavors have settled. For longer storage, freeze them in a single layer on a baking sheet until solid, then transfer to a freezer bag or container with parchment between layers; they keep well for up to 2 months. Thaw overnight in the fridge. Skip reheating entirely — these are meant to be served cold or at room temperature, and warming them softens the filling too much. Add fresh powdered sugar after thawing.
Classic Lemon Bars
Equipment
- 9×13-inch (33×23cm) baking pan
- Parchment paper
- Medium mixing bowl
- Large mixing bowl
- Whisk
- Wire cooling rack
- Fine-mesh sieve (for dusting powdered sugar evenly)
Ingredients
For the Shortbread Crust
- 1 cup unsalted butter softened, 225g
- ½ cup granulated sugar 100g
- 2 cups all-purpose flour 250g
- ¼ teaspoon salt
For the Lemon Filling
- 1 ½ cups granulated sugar 300g
- ¼ cup all-purpose flour 30g
- 4 large eggs
- ⅔ cup freshly squeezed lemon juice 160ml, about 5-6 medium lemons
- 1-2 teaspoons lemon zest finely grated, optional for more vibrant flavour
For Serving
- ¼ cup powdered sugar for dusting, 30g
Instructions
- Preheat your oven to 350°F / 175°C (160°C fan-forced). Grease a 9×13 inch (33x23cm) baking pan with butter and line with parchment paper, leaving a 2-inch (5cm) overhang on two sides for easy removal.
- For the crust: In a medium mixing bowl, cream together the softened butter and sugar until light and fluffy — about 3-4 minutes with a hand mixer, or 5-6 minutes by hand. Add the flour and salt, mixing on low speed (or by hand with a wooden spoon) until just combined and the mixture forms a crumbly dough. Do not overmix.1 cup unsalted butter, 1/2 cup granulated sugar, 2 cups all-purpose flour, 1/4 teaspoon salt
- Press the dough evenly into the prepared baking pan, creating a smooth layer. Bake in the preheated oven for 15-20 minutes or until lightly golden at the edges. Set aside to cool slightly.
- For the filling: In a large bowl, whisk together the sugar and flour. Add the eggs, lemon juice, and lemon zest (if using), whisking until fully combined and smooth.1 1/2 cups granulated sugar, 1/4 cup all-purpose flour, 4 large eggs, 2/3 cup freshly squeezed lemon juice, 1-2 teaspoons lemon zest
- Pour the lemon mixture over the pre-baked crust, spreading evenly. Return to the oven and bake for an additional 20-25 minutes, or until the filling is set — it should move as one solid piece when you gently shake the pan, with no liquid jiggling in the centre. The edges may puff slightly and the surface should look matte, not glossy.
- Cool completely on a wire rack. Once cooled, refrigerate for at least 2 hours before slicing into bars. Dust with powdered sugar before serving.1/4 cup powdered sugar
Notes
Nutrition
FAQ
Can I make these a day ahead?
Yes — and it’s actually the better option. The filling firms up more completely overnight, which makes slicing much cleaner. Just hold off on the powdered sugar until right before you serve them.
How do I know when the filling is done baking?
The filling is done when it no longer jiggles in the center when you gently shake the pan. The edges may look slightly more set than the middle, but the whole surface should move as one piece rather than sloshing.
My filling cracked on top — what happened?
Cracking usually means the bars were overbaked or the oven ran hot. It doesn’t affect the flavor at all, and the powdered sugar covers it completely — skip the garnish stress and just dust generously before serving.
Can I use a different size pan?
You can use a 9×9-inch pan, but the bars will be thicker and will need a few extra minutes of baking time for both the crust and the filling. Check for doneness by the jiggle test rather than by time alone.
Is the lemon flavor very strong? Will kids eat these?
The flavor is tangy but balanced by the sugar — most kids who like lemonade take to these easily. If you want a milder result, reduce the lemon juice slightly and make up the difference with a tablespoon or two of water.
Can I double the recipe?
Doubling works well if you use two 9×13 pans rather than one larger one — spreading the batter too thick in a single pan makes it hard to bake the filling through evenly. Baking times stay roughly the same.
