blueberry streusel muffins

Ingredients
1 cup milk
1/4 cup vegetable oil
1/2 teaspoon vanilla extract
1 egg
2 cups all-purpose flour or whole wheat flour
1/3 cup sugar
3 teaspoons baking powder
1/2 teaspoon salt
1 cup fresh blueberries or canned blueberries, drained
STREUSEL TOPPING
1/4 cup all-purpose flour
2 tablespoons packed brown sugar
2 tablespoons butter
Directions
1Heat oven to 400 degrees.
2Grease bottoms only of 12 medium muffin cups, 2-1/2 X 1-1/4 inches, or paper lined cups.
3Beat the milk, oil, vanilla extract and egg.
4Stir in the flour, sugar, baking powder & salt all at once until flour is moist (should be lumpy). Add the blueberries, combine and divide batter evenly among muffin cups.
5Sprinkle each using about 2 tsp of the prepared topping.
6Bake 20-25 minutes or until golden brown.
7Remove from pan right away.