Preheat your oven to 350°F (175°C) and place a rack in the center position. Line an 8-inch square pan with parchment paper, leaving handles on one side for easy lifting if your pan isn't non-stick.

In a medium bowl, mix the melted butter, sugar, and lemon zest. Whisk until well combined.

Add the egg and 2 egg yolks, whisk thoroughly. Save the extra egg whites for another recipe.

Stir in the lemon juice and mix well.

Sprinkle the flour, baking powder, and salt evenly over the bowl. Stir until just combined. *Tip: Be careful not to overmix; this keeps the brownies tender.*

Spread the batter in the prepared 8-inch square pan. Bake for 25-27 minutes until the edges crackle and turn golden brown. Remove from the oven and let cool slightly.

For easy cutting, transfer the brownies to the freezer for 15-20 minutes. Once chilled, lift them out of the pan using the parchment paper handles and cut into 16 squares.

To make the glaze, whisk together the powdered sugar, lemon juice, and lemon zest. Drizzle over the brownies and serve.