Beat together 1/2 cup butter/margarine and 1/2 cup sugar untill creamy. Add egg, milk, and vanilla. Stir in 2 cups flour, salt, and baking powder. Pour into a greased 7X12" pan. Cover with blueberries.
In a seperate bowl combine topping ingredients of 1/2 cup sugar, 1/2 cup flour, cinnamon,and 1/4 cup butter/margarine
untill crumbly. Sprinkle over the top of blueberries.
Bake in a preheated 350 degree oven for 40 to 45 minutes.
Let rest for 5 minutes. Serve hot. We like to add a dollop of homemade lemon curd.