1/2 cup butter, room temperature
2 teaspoons lemon zest
3/4 cup + 2 Tablespoons sugar, divided
1 egg, room temperature
1 teaspoon vanilla extract
2 cups flour, divided
2 teaspoons baking powder
1 teaspoon kosher salt
2 cups fresh blueberries
1/2 cup buttermilk
Preheat oven to 350 degrees. Cream butter, lemon zest and 3/4 cup + 1 Tablespoon of the sugar together. Beat until creamy and fluffy. Add egg and vanilla and beat until combined.
Meanwhile, toss the blueberries with 1/4 cup of the flour. Set aside.
Whisk together the remaining flour, baking powder and salt together in a seperate bowl. Slowly add flour mixture to wet mixture, alternating with the buttermilk. Fold in blueberries.
Grease a 9x9 inch square pan with non-stick spray. Spread batter into pan (batter will be thick).
Sprinkle the remaining Tablespoon of sugar evenly over the top of batter.
Bake for 35-40 minutes, or until a toothpick inserted comes out clean. Let cool 15 minutes before serving.