To prepare blueberry filling, combine all ingredients in a bowl to use in the cobbler recipe.Preheat oven to 375 degrees.
Mix flour, baking powder and salt in a small bowl and then set aside.
Beat butter and sugar until fluffy on medium high with an electric mixer.
Beat in egg yoke and vanilla until mixed thoroughly. Stir in dry ingredients until just combined.
Place fruit mixture into an 8-inch square baking pan or 9-inch round deep dish pie plate. Drop cookie dough topping evenly over fruit mixture. Try to make sure the cookie dough isn't touching.
Bake until golden brown, 45-55 minutes. Place a piece of tin foil over the cobbler if cookie dough gets too brown before it's done baking. Serve warm. Pairs well with vanilla ice cream.
Although we enjoy this Blueberry Cobbler a lot during the summertime, it can be made with frozen blueberries anytime. We just have a little obsession with berry picking because there's nothing better than fruit picked at the peak of freshness!