Ingredients

• 0.75 cups unsalted butter
• 0.5 cups white sugar
• 0.5 cups light brown sugar
• 0.75 teaspoons salt
• 2 teaspoons vanilla extract
• 2 cups all-purpose flour
• 0.25 teaspoons baking powder

Instructions

1. 1 Preheat the oven to 350 degrees F (180 degrees C). Line a 9x9-inch square pan with enough parchment paper to have overhang on all sides.
2. 2 For crust and crumb, stir together melted butter, white sugar, brown sugar, salt, and vanilla until thoroughly combined. Add in flour and baking powder and mix until mixture comes together in large clumps. Measure out a loosely-packed 1 3/4 cups crumbs and press firmly and evenly into the bottom of prepared pan. Reserve remaining crumb mixture for topping.
3. 3 Break an egg into a large bowl and whisk for a few seconds. Lightly brush a thin layer of egg over the crust; you will use any egg left in the filling. Place crust into the freezer for about 10 to 15 minutes while you prepare filling.
4. 4 For filling, to the egg you used as egg wash, add the remaining 2 eggs, 1 cup plus 2 tablespoons sugar, cornstarch, lemon zest, and pinch salt. Whisk until completely smooth and combined. Whisk in the 3 tablespoons melted butter until incorporated. Pour in lemon juice and whisk until combined.
5. 5 Remove crust from freezer and pour the filling evenly over the top.
6. 6 Bake bars in the preheated oven for 25 minutes.
7. 7 Remove pan from oven and sprinkle reserved crumb topping evenly over the top, breaking up any larger crumbs as needed. Return pan to the oven.
8. 8 Bake until crumbs just begin to turn golden, 20 to 25 minutes more. Allow bars to cool completely, about 30 minutes, before cutting and serving.

Nutrition per serving