Preheat oven to 300℉ and line a 13x9 pan with parchment paper.

In a stand mixer, fitted with the whisk attachment, mix the flour, butter, sugar and salt together. Mix on a low speed until the butter is broken up into a small crumble texture.

Press the mixture into the pan and form edges up the side of the pan about an inch to an inch and a half.

Bake crust for about 25 minutes or until golden brown.

Let the crust cool while mixing the filling.

In a medium bowl, mix together the eggs and sugar with a whisk. Then add in the lemon zest and lemon juice. Finally add in the flour and baking powder.

Pour mixture in cooled crust and transfer to oven. Bake for about 35 minutes or until the filling has just a slight jiggle.

Let bars cool completely before cutting so that the filling is set.

Use a strainer or sifter to cover lemon bars with confectioners sugar.