Ingredients
For shortbread
1.5 sticks butter
2 cups flour
1 tsp vanilla
1/2 cup brown sugar
0.5 tsp salt
For filling
4 large eggs
1.5 cup sugar
0.5 cup lemon juice
1/3 cup flour
Directions
Preheat Oven to 350
Line the bottom and sides of a 9×13 baking pan* with parchment paper, leaving an overhang on the sides to lift the finished bars out (makes cutting easier!). Set aside.
Make the crust:
Mix the melted butter, sugar, vanilla extract, and salt together in a medium bowl. Add the flour and stir to completely combine. The dough will be thick. Press firmly into prepared pan, making sure the layer of crust is nice and even. Bake for 18-20 minutes or until the edges are very lightly browned.
Remove from the oven and set aside until step 4.
Make the filling:
Sift the sugar and flour together in a large bowl. Add the eggs and lemon juice and whisk until completely combined.
Pour filling over warm crust. Bake the bars for 22-26 minutes or until the center is relatively set and no longer jiggles. (Give the pan a light tap with an oven mitt to test.)
Remove bars from the oven and cool completely at room temperature. I usually cool them for about 2 hours at room temperature, then stick in the refrigerator for 1-2 more hours until pretty chilled. I recommend serving chilled.