Huckleberry Hand Pies

Pastry

--2 cups Unbleached All-Purpose Flour

--1/2 teaspoon salt

--1/2 teaspoon baking powder

--1 cup (16 tablespoons) cold unsalted butter

--1/2 cup cold sour cream

Filling

--2 cups blueberries, fresh or frozen

--1/4 cup sugar

--1 tablespoon Instant ClearJel

--2 teaspoons lemon juice

Topping

--1 large egg, beaten

--white sparkling sugar, for garnish