Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking pan with non-stick spray or line it with parchment paper.

In a large mixing bowl, blend the melted butter and granulated sugar together until smooth and glossy.

Add in the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract, followed by the flour, baking powder, salt, lemon zest, and lemon juice. Mix until just combined.

Pour the batter into the prepared pan and spread it evenly.

Bake in the preheated oven for 20-25 minutes, or until the edges are golden and a toothpick inserted into the center comes out clean.

Let the brownies cool in the pan for about 10-15 minutes before cutting into squares.

Dust with powdered sugar if desired.