FOR THE CRUMBLE:
Mix together until crumble like consistency and set aside.
FOR THE CAKE:
Mix the butter and sugar until creamy. Add the eggs and vanilla. Finally alternate the dry ingredients with the milk until you have a uniform mixture. Fold in half the blueberries.
Place baking paper in a 12 inch by 9 inch baking pan and spray with cooking spray. Place the rest of blueberries on top scattered though out. Place all the crumble mixture on top and bake at 375F in a conventional home oven for 40-50 min or until a toothpick comes out clean.