Preheat oven to 350℉. Coat an 8-inch skillet or pan with Wilton cake release. In the bowl of your stand mixer, beat butter and sugar until light and fluffy.
½ cup butter, ¾ cups granulated sugar
Add eggs and vanilla.
1 large egg, 1 teaspoon vanilla extract
In another bowl, combine flour, baking powder, and salt. Add flour mixture to butter mixture one cup at a time, mixing after each addition.
1 and ⅓ cups all-purpose flour, ½ teaspoon baking powder, ½ teaspoon salt
Carefully fold in blueberries. Spoon dough into an 8-inch oven-safe skillet or cake pan. Bake in 350℉ for 30 to 35 minutes or until the center of the cookie is done.
1 cup blueberries
Chill for 5 minutes before serving. This cookie is great served with vanilla ice cream.