Prepare the Pan and Oven: Preheat the oven to 350°F. Spray a 9×13-inch cake pan with cooking spray. For easier removal, the pan may also be lined with parchment paper or aluminum foil.
Cream the Butter and Sugar: Place the softened butter and sugar in the bowl of an electric mixer. Beat until the mixture becomes light and fluffy.
Add the Eggs: Add the eggs one at a time, beating after each addition until fully incorporated before adding the next egg.
Add the Lime: Mix in the key lime juice and lime zest until incorporated.
Finish the Batter: Slowly add the all-purpose flour and salt, mixing only until the ingredients are just combined.
Fill the Pan: Pour the prepared batter into the greased 9×13-inch pan and spread it evenly.
Bake the Brownies: Bake at 350°F for 30 minutes.
Cool Completely: Remove the pan from the oven and allow the brownies to cool before adding the glaze.
Make the Glaze: Combine the powdered sugar, key lime juice, and lime zest, mixing until the glaze is combined.
Glaze the Brownies: Pour the key lime glaze over the cooled brownies and allow it to set before cutting the dessert into bars.
