1 1/3 cups all-purpose flour
1 cup firmly packed brown sugar
2/3 cup all-purpose flour
1 1/2 teaspoons baking powder
1 1/2 teaspoons ground cinnamon
1/2 teaspoon baking soda
1/2 teaspoon salt
2/3 cup buttermilk*
1 cup fresh or frozen blueberries
Heat oven to 400°F. Combine 1 1/3 cups flour and brown sugar; cut in butter with pastry blender or fork until mixture resembles coarse crumbs. Reserve 1/2 cup for streusel topping.
Add all muffin ingredients except blueberries to remaining streusel mixture. Stir just until moistened. Gently stir in blueberries.Spoon mixture evenly into paper-lined or greased muffin cups.
Sprinkle each muffin with about 1/2 tablespoon reserved streusel mixture. Bake for 20 to 25 minutes or until lightly browned. Cool 5 minutes; remove from pans.
*Substitute 2 teaspoons vinegar plus enough milk to equal 2/3 cup. Let stand 10 minutes.
To make coffeecake, heat oven to 375°F. Prepare as directed. Spread batter into greased 13x9-inch baking pan; sprinkle with reserved streusel mixture. Bake for 30 to 35 minutes or until light golden brown. Cool 10 minutes; cut into squares.