Step 1

Preheat oven to 350° F. Grease a 9x13-inch glass baking dish with cooking spray and line with parchment paper, leaving a slight overhang on the two long ends (this can be used to easily remove the lemon bars from the pan).

Step 2

To make the crust, cream together the butter and powdered sugar with a stand mixer or hand mixer until well combined. Mix in the vanilla extract. Then mix in the flour and salt until combined. The dough may be crumbly.

Step 3

Firmly press the dough into the prepared baking dish. (This takes a bit of work but be patient and it will press out into an even layer.) Bake for 17-20 minutes, until barely golden brown. Set aside to cool for a few minutes.

Step 4

To make the lemon filling, add the sugar and lemon zest to a large bowl. Use your fingers to work the zest into the sugar until fragrant.

Step 5

Add the flour and whisk until well combined.

Step 6

Add the eggs and lemon juice and whisk until well combined.

Step 7

Pour the lemon filling over the warm crust. Use oven mitts to carefully return the pan to the oven and bake for 20-25 minutes, until center is set and jiggles only slightly when you gently shake the pan. Let the bars cool at room temperature for about an hour, then chill in the refrigerator for at least 2 hours before slicing and serving. To cut clean slices, lightly spray a sharp knife with cooking spray and wipe with a damp paper towel between cuts as needed.

Step 8

Sprinkle lemon bars with powdered sugar right before serving, if desired.