Blueberry Streusel Muffins recipe.

Ingredients
1/3 cup sugar
1/4 cup butter or margarine, softened
1 egg, beaten
2 1/3 cups all-purpose flour
4 teaspoons baking powder
1/2 teaspoon salt
1 teaspoon vanilla extract
1 1/2 cups fresh or frozen blueberries
1/2 cup sugar
1/3 cup all-purpose flour
1/2 teaspoon ground cinnamon
1/4 cup butter or margarine

Directions
In a mixing bowl, cream sugar and butter. Add egg; mix well. Combine flour, baking powder and salt; add to the creamed mixture alternately with milk. Stir in vanilla. Fold in blueberries. Fill 12 greased or paper-lined muffin cups two-thirds full. In a small bowl, combine sugar, flour and cinnamon; cut in butter until crumbly. Sprinkle over muffins. Bake at 375 degrees F for 25-30 minutes or until browned.