Preheat the oven to 350F degrees and prepare an 8x8-inch baking pan by spraying generously with non-stick spray and line the bottom with parchment paper. Set aside.
In a large mixing bowl. Mix 1 box lemon cake mix, 2 large eggs, 1/3 cup unsalted butter, melted and 1 teaspoon lemon extract. Mix until just combined, the mixture will be thick!
Press the mixture (it will be thick) into the prepared baking dish and bake 18-20 minutes or until a toothpick inserted in the center of the brownies comes out clean.
Remove from the oven and allow to cool completely on a wire rack.
To make the glaze, whisk together ¾ cup powdered sugar, 1 teaspoon lemon extract and 1 ½ Tablespoons milk in a medium bowl and whisk until combined.
Pour over the cooled brownies and smooth evenly.
Cut into 9 pieces and serve!
Notes
You can make a double batch if desired.
Store in an airtight container for up to 3 days. Or freeze for up to 3 months.