Blueberry Buttermilk

½ cup (1 stick) unsalted butter, softened
Zest of 1 lemon
½ cup of sugar
1 egg
2 cups flour
1 teaspoon salt
2 teaspoons baking powder
2 cups fresh or frozen blueberries
½ cup buttermilk
1 teaspoon vanilla extract
-Preheat oven to 350 degrees f and butter an 8-inch square pan.
-In a bowl, whisk softened butter with lemon zest and sugar until fluffy.
-Add vanilla extract and egg.
-In a large bowl, combine flour, salt, and baking powder.
-Coat blueberries with ¼ cup of the flour mixture.
-Add remaining flour to the butter mixture, alternating with buttermilk.
-Gently fold in blueberries.
-Pour batter into pan.
-Bake for 35 to 45 minutes.