Mix ingredients together in a bowl until crumbly. Set aside.
Cake
2 cups flour 1 cup sugar 1/4 cup butter 3/4 cup milk 1 egg 1 tsp salt 2 1/2 tsp baking powder 2 1/2 cups blueberries
Prepare an 8x8 pan with baking spray. Combine all cake ingredients except blueberries. Gently fold in blueberries. Spread batter in prepared pan. Sprinkle crumb mixtures evenly over top.
Bake for 45 minutes in a 375 oven.
When cool drizzle glaze over top. (I only made 1/2 the recipe for the glaze and it was more than enough.)