Preheat your oven to 350°F (175°C).
Line a 9x13 inch baking pan with parchment paper.
Cream together the softened unsalted butter, packed brown sugar, and granulated sugar until light and fluffy.
Add the eggs, lemon extract, lemon juice, and lemon zest; mix until well combined.
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually add to the wet ingredients.
Pour the batter into the prepared baking pan and spread evenly.
Bake for 20-25 minutes or until a toothpick inserted comes out clean.
Cool in the pan for about 10 minutes, then transfer to a cooling rack.
In a small bowl, whisk together the powdered sugar and lemon juice for the glaze.
Drizzle the glaze over the cooled blondies and let it set before cutting into squares.
