Preheat your oven to 350 degrees F. Grease a 9x13-inch baking pan with non-stick cooking spray or line it with parchment paper.
In a large bowl, cream together the softened butter and sugar until it's light and fluffy.
Beat in the eggs one at a time until fully combined.
Then stir in the lemon juice and lemon zest.
In a separate small bowl, whisk together the flour, salt, and baking powder.
Gradually add the dry ingredients into the butter mixture and mix until combined.
Spread the batter evenly into the prepared pan.
Place in the oven and bake for 25-30 minutes, or until the edges start to turn golden and a toothpick inserted into the center comes out clean.
Remove from the oven and allow the brownies to cool completely in the pan on a wire rack.
While the brownies are cooling, prepare the glaze. In a small bowl, whisk together the powdered sugar, lemon juice, and lemon zest until smooth.
Once the brownies are cooled, drizzle the glaze over the top. Allow the glaze to set before cutting the brownies into squares.