A sweet treat that uses common ingredients. I like to add cinnamon to the crumb topping, but it's good either way. Margarine or shortening will work instead of butter in this recipe. If you don't have sour milk you can make it by adding 1 tablespoon of lemon juice or vinegar in a measuring cup and filling with milk to the one-cup measurement. Stir and let stand at room temperature for 10 minutes. You'll have sour milk for the recipe.