No one can resist a square of crumble-top coffee cake. This Blueberry Buckle Coffee Cake achieves both fluffiness and a buttery crisp streusel. Any fruit will work, but berries are best!
In a large bowl, beat softened butter and sugar until blended. Add milk, vanilla extract and egg.
In another bowl, combine flour, baking powder and salt. Add to butter mixture and mix just until combined. The batter will be very thick.
Carefully fold in blueberries.
Scoop the mixture into buttered pan and gently press it out evenly.
Combine all topping ingredients in food processor or use a fork/fingers to combine until crumbles (large and small) form. Sprinkle evenly over batter.