Preheat the oven to 350 degrees F and grease a 9 X 13 inch baking dish with cooking spray.
In the bowl of a stand-up mixer, cream together the butter and sugar on high speed.
Add the eggs one at a time mixing between each addition.
Add the lemon juice and vanilla extract and mix to combine.
Right on top of the wet ingredients, add the all-purpose flour, double-acting baking powder, salt, and fresh lemon zest. Mix on low speed until combined. Do not over-mix.
Pour the batter into the prepared baking dish, smooth with a rubber spatula, and bake for 20 minutes or until a toothpick inserted into the center comes out clean.
Allow to cool for 5-10 minutes before transferring to a wire rack and cooling completely.
Lemon Frosting
In the bowl of a stand-up mixer, cream together the butter, cream cheese, and lemon juice on medium-high speed until smooth.
Add the powdered sugar and mix on low speed until incorporated.
Spread the frosting over the cooled lemon brownies and sprinkle with lemon zest.
Notes
To store the brownies for next time, place them in an airtight container at room temperature for 3-4 days or freeze them individually with plastic wrap and store them in a freezer-safe bag for up to 3 months.