Homemade lemon bars have a buttery shortbread base and a thin, sweet-tart lemon custard made with eggs, fresh juice, and zest. This nine-inch square pan makes nine generous bars with a light powdered sugar finish.
Bake the crust before adding the filling, then allow time for both cooling and chilling. These bars are fairly sweet and have a tender custard layer; cutting them warm can leave the filling and crust on the knife.
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Why This Recipe Works
The first bake firms the butter-and-flour crust so it can support the liquid filling. Eggs provide the custard structure, while lemon zest adds concentrated citrus aroma without extra liquid. Cooling lets the filling settle, and chilling makes the shortbread easier to portion cleanly.
Ingredients
Measure flour by spooning it into the cup and leveling it. Softened butter should yield to a fingertip while still holding its shape. The powdered sugar belongs in the crust, while granulated sugar sweetens the filling. Zest the lemon before squeezing it and take only the yellow peel; the white pith tastes bitter. Measure a full quarter cup of juice rather than relying on the size of one lemon. A light-colored metal pan is useful for an evenly baked base.
For the crust
- 1 cup all-purpose flour, spooned and leveled
- 1/2 cup powdered sugar, for the crust
- 1/2 cup unsalted butter, softened
For the filling
- 1 cup granulated sugar
- 2 large eggs
- 1/4 cup fresh lemon juice
- 1 teaspoon lemon zest
- 1/2 teaspoon baking powder
- Pinch salt
- powdered sugar, additional, for dusting
As Needed
- butter or cooking spray, as needed to grease the pan
How to Make Homemade Lemon Bars
1. Press an even base. Heat the oven to 350°F and lightly grease a nine-inch square pan. Mix the crust flour and powdered sugar, then work in the soft butter until small moist clumps form. The mixture may look crumbly rather than like smooth cookie dough. Press it firmly across the bottom, especially into the corners, keeping the thickness even so thin patches do not brown before the center.
2. Bake the crust first. Bake the base for about fifteen to twenty minutes until set and lightly golden at the edges. A deeply brown crust can become hard after its second bake. Meanwhile, whisk the eggs and granulated sugar thoroughly, then add lemon juice, zest, baking powder, and a pinch of salt. Beat for two to three minutes until the mixture looks lighter and the sugar is well dispersed.
3. Set the custard. Pour the filling over the hot crust and return the pan to the oven promptly. Allow another twenty-five to thirty minutes, checking the center as well as the edges. The surface should look set, with no liquid sloshing when you gently nudge the pan; an egg custard should reach 160°F at the center. Baking far beyond this point can dry the edges and cause cracks.
4. Cool before slicing. Leave the pan on a rack for about an hour, then refrigerate for at least another hour until fully chilled. This resting period is part of the total recipe time. Dust the cold surface lightly with powdered sugar just before cutting into a three-by-three grid. Wipe the knife between cuts so crumbs and sticky custard do not drag across the next square.
How to Serve
Serve one chilled bar per person, or cut the nine large squares in half for smaller dessert portions. A little powdered sugar is enough to finish the sweet filling. For a dessert tray, arrange the pieces in a single layer and bring out small batches from the refrigerator as needed.
Storage
Refrigerate the bars covered at 40°F or below for up to five days, placing parchment between layers if stacking is necessary. Refrigerate within two hours of baking; the initial cooling hour counts toward that window. Add powdered sugar shortly before serving because it dissolves on a moist surface. These custard bars are best kept refrigerated rather than frozen, which can soften the crust and make the filling weep. See federal cold-storage guidance for refrigerated foods.
Tips and Variations
- Measure the juice separately from the zest.
- Keep the base level, with no thin corners.
- Beat the filling while the crust bakes so it is ready for the hot pan.
- Chill completely and wipe the knife between cuts.
Frequently Asked Questions
Can I use bottled lemon juice?
It works in the same measured amount. Fresh juice and zest give a brighter citrus aroma.
Can I use an eight-inch pan?
The layers will be thicker. Expect a longer bake and check the center rather than relying on the nine-inch-pan timing.
Why did powdered sugar disappear?
The moist custard absorbs it during storage. Dust the surface again just before serving.
Can I reduce the sugar substantially?
Sugar affects both the custard and the crust texture. A recipe formulated for less sugar is a better starting point for a large reduction.
Can I use lime instead?
An equal amount of lime juice and lime zest creates a lime variation. Its tartness will differ slightly from lemon.
More Recipe Ideas
Homemade Lemon Bars
Ingredients
For the crust
- 1 cup all-purpose flour spooned and leveled
- 1/2 cup powdered sugar for the crust
- 1/2 cup unsalted butter softened
For the filling
- 1 cup granulated sugar
- 2 large eggs
- 1/4 cup fresh lemon juice
- 1 teaspoon lemon zest
- 1/2 teaspoon baking powder
- Pinch salt
- powdered sugar additional, for dusting
As Needed
- butter or cooking spray as needed to grease the pan
Instructions
Bake
- Heat oven to 350°F. Lightly grease a 9-inch square baking pan.
- Mix 1 cup flour and 1/2 cup powdered sugar, then work in softened butter until clumpy. Press evenly into the pan and bake 15–20 minutes until set and lightly golden at the edges.
- Beat eggs and granulated sugar, then add lemon juice, zest, baking powder, and salt. Beat 2–3 minutes until light and evenly blended.
- Pour filling over the hot crust. Bake at 350°F for 25–30 minutes until the center is set without liquid movement and reaches 160°F.
Cool and Cut
- Cool in the pan on a rack for about 60 minutes, then refrigerate at least 60 minutes until completely chilled.
- Dust with additional powdered sugar and cut into 9 bars. Refrigerate until serving.
Notes
- Refrigerate covered for up to 5 days; chill within 2 hours of baking.
- Add powdered sugar just before serving.
