In a medium mixing bowl, combine the butter, ½ cup sugar, and 2 cups flour. Mix until fully combined. Press the dough into an ungreased 9-inch x 13-inch baking pan.
Bake for 15-20 minutes, or until the edges are golden.
While the crust bakes, whisk the remaining 1 ½ cups sugar, ¼ cup flour, eggs, and lemon juice in a medium mixing bowl until well combined.
Pour the lemon mixture over the warm crust and bake for another 20 minutes.
Remove from the oven and let cool for 1 hour on the counter. Then transfer the pan to the fridge for 1-2 hours. Once cooled, sprinkle the top of the bars with powdered sugar before cutting into 15 squares.
Notes
If you don't have salted butter on hand, you can substitute 1 cup of unsalted butter and add 1/2 teaspoon of salt to the butter/flour mixture.