Preheat oven to 350 degrees. Place paper liners in muffin pans. This makes 2 dozen.
1/2 cup all-purpose flour
1/2 cup sugar
4 tablespoons butter, slightly softened and cut into 1/2 inch pieces
In a medium bowl, stir flour and sugar. Add butter pieces and combine mixture with a fork until topping resembles coarse crumbs. Set aside
2-1/2 cups all purpose flour
2 teaspoon baking powder
1/2 teaspoon baking soda
1-1/2 sticks butter (room temp.)
1-1/2 cups sugar
3 large eggs, (room temp.)
1-1/2 teaspoon vanilla extract
8 ounces sour cream
1/4 cup milk
2-1/2 cups fresh blueberries
In a medium bowl, sift flour, baking powder and baking soda.
With an electric mixer fitted with a paddle attachment, cream the butter and sugar until light and fluffy (about 5 minutes).
At low speed, beat in one egg at a time, then add vanilla, sour cream, and milk until combined.
Add 1/3 of dry ingredients at a time and beat until just combined.
With a spatula, evenly fold blueberries into batter.
Spoon batter into muffin pans and fill each cup to the top.
Sprinkle streusel topping over batter.
Bake for 30-35 minutes until a toothpick comes out clean.