Heat oven to 375°F. Combine milk, 1/2 cup melted butter and egg in large bowl. Add all remaining muffin ingredients except blueberries; stir just until flour is moistened. Gently stir in blueberries.
Spoon batter into greased or paper-lined muffin pan. Bake for 22 to 25 minutes or until golden brown. Cool slightly; remove from pan.
Dip tops of muffins in 1/4 cup melted butter, then in 1/4 cup sugar.