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Baking · American

Lemon Bars

A crisp buttery base under a sharp, sunny lemon layer.

Hands-on
10 min
Hands-off
3 h 5 min
Oven preheat
15 min
Total
3 h 15 min
Makes
16 bars
Serves
16

Preheating overlaps making the crust. Hands-off time: about 35 min crust bake, about 30 min filling bake (the filling rests while the crust bakes), then about 2 hours to cool and chill before slicing. Total = 10 min active + 185 min hands-off. Many recipes list about 1 h 10 min because they leave out cooling.

Oven 180 °C · 160 °C fan, then 170 °C · 150 °C fan (350 °F, then 325 °F)

Pan 20 cm square pan, lined with parchment (US: 8-inch square pan, lined with parchment)

  • easy
  • vegetarian
  • lemon
  • bar-cookies
  • make-ahead
  • spring

Verified against at least two trusted test kitchens or food-safety guides · Last checked · What this means

Illustration of Lemon Bars
Amount
Units
Oven

Ingredients

You need: 20 cm (8 in) square baking pan · parchment paper · 2 mixing bowls · whisk · fork or pastry blender · wire rack · sharp knife · fine sieve for dusting · oven mitts · instant-read thermometer (optional)

Contains: egg · milk · wheat

Method

  1. Heat the oven, line the pan

    Heat the oven to 180°C (160°C fan, 350°F) and line the 20 cm (8 in) square pan with parchment, leaving the paper sticking up over two sides so you can lift the bars out later.

  2. Make the crust

    Whisk 120 g (1 cup) flour, 1/4 tsp salt and 28 g (1/4 cup) confectioners' sugar in a bowl. Work in 113 g (8 tbsp) soft butter with a fork or your fingertips until it is evenly spread through; the mix will look crumbly.

  3. Press it in firmly

    Press the crumbs into the lined pan in an even, tightly packed layer with no gaps. If the dough sticks to your hands, put the pan in the freezer for 5 to 10 minutes, then keep pressing. A firm crust stops the filling from running underneath.

    Otto tried this firstOtto pats the crumbs in loosely and calls it done. The filling then sneaks under the crust and the bars come out soggy-bottomed. Press hard, all the way into the corners.

  4. Bake the crust

    Bake the crust for 30 to 35 minutes.

    Ready when: Golden brown all over, darker at the edges.

  5. Mix the filling while the crust bakes

    Whisk 4 eggs, 1 egg yolk, 223 g (1 cup + 2 tbsp) granulated sugar and 21 g (3 tbsp) confectioners' sugar until smooth. Whisk in 30 g (1/4 cup) flour and 1/8 tsp salt, then 152 g (2/3 cup) lemon juice until fully combined. Let it stand about 15 minutes so most of the bubbles rise and pop.

  6. Turn the oven down

    Take the baked crust out and lower the oven to 170°C (150°C fan, 325°F).

    Ready when: The crust is golden brown and stays warm while the oven cools to the lower setting.

    Otto tried this firstOtto forgets to turn the oven down. At the higher heat the lemon layer can brown and puff at the edges before the middle sets.

  7. Fill and bake

    Pour the filling over the hot crust and put the pan back in the oven. Bake for about 30 minutes.

    Ready when: The filling looks set and fairly dry on top and doesn't ripple when you gently nudge the pan. With a thermometer, the centre of the filling reads at least 71°C (160°F), the food-safety target for egg dishes.

  8. Cool, chill, slice

    Cool the bars completely in the pan on a wire rack, then refrigerate until firm, at least 2 hours in total. Lift the slab out by the parchment, cut into 16 squares with a sharp knife, and dust with confectioners' sugar just before serving.

Swaps

  • Instead of confectioners' sugar for dusting: non-melting topping sugar Stays white on the moist lemon layer instead of soaking in.
  • Instead of parchment sling: foil with a 5 cm (2 in) overhang, greased on both the pan and the foil Either liner lets you lift out the whole slab and cut it on a board.

Make ahead, store & reheat

Make ahead
Bake the bars up to a day ahead and keep them covered in the fridge; dust with sugar just before serving.
Storage
The lemon layer is an egg custard: keep the bars covered in the fridge and eat within 3 to 4 days. Don't leave them out for more than 2 hours (1 hour above 32°C / 90°F).

If something goes wrong

  • Filling seeped under the crust Why: The crust was pressed in loosely or had cracks.
    Pack the crumbs firmly and evenly, all the way to the edges, before baking.
  • Foamy, bubbly top Why: The filling went in straight after whisking.
    Let the filling rest about 15 minutes so the bubbles settle before pouring.
  • Messy, gooey slices Why: Cut while still warm.
    Cool completely and chill at least 2 hours, then lift out on the liner and cut on a board.

Good to know

  • For more lemon flavour, mix the finely grated zest of 1 lemon into the crust before pressing it in.
  • Dust with sugar right before serving; on chilled bars it slowly melts into the filling.
  • In a glass or ceramic pan, allow a few extra minutes of baking.

Safety

  • Don't taste the raw filling or crust dough: they contain raw egg and raw flour. Only the baked bars are ready to eat.
  • Wash hands, bowls and the counter after handling raw flour and eggs.
  • The pan is very hot when you pour the filling onto the crust. Use oven mitts; kids should let an adult move the pan in and out of the oven.
  • Refrigerate the bars: bacteria can grow in an egg filling left warm.