Preheat oven to 350 degrees. Spray a 9x9 baking pan cooking spray or line with foil and set aside.

In a large mixing bowl, beat together butter, sugar, and lemon zest until light and fluffy. Add eggs one at a time and continue to mix.

Add lemon juice, flour and baking powder, and mix until well combined.  Stir in blueberries.

Pour batter into prepared pan and smooth into an even layer.

Bake for 25 minutes, or until a toothpick inserted into the blondies comes out clean. Let blueberry lemon blondies cool for 10-15 minutes.

To make the glaze, whisk together powdered sugar, lemon juice, half and half, and lemon zest.

Pour over blondies and spread evenly to coat.

Let blondies cool completely before slicing and serving.