Preheat your oven to 350°F and prepare an 8×8 pan with cooking spray or parchment paper.

Beat together the softened butter, granulated sugar, and lemon zest until light and fluffy.

Add eggs one at a time to the butter mixture, mixing well after each addition, then add fresh lemon juice.

Combine the flour and baking powder into the batter, stirring until just combined.

Pour the batter into your prepared pan, smoothing it out evenly.

Bake for 20–25 minutes, or until a toothpick inserted comes out clean.

Cool the brownies in the pan for 10–15 minutes before transferring to a wire rack.

Whisk together the glaze ingredients in a bowl, then pour over the cooled brownies.

Spread the glaze evenly and let the brownies cool completely before slicing.