Preheat oven to 350℉ (180℃) degree.
Melt butter in a 9x13 inch baking dish.
Add all ingredients except the blueberries in a large mixing bowl.
Mix well; then, when margarine is melted, pour the ingredients into the baking dish.
Add the blueberries.
Don't mix them in; just add them.
Bake at 350℉ (180℃) about 1 hour, until until the top is golden-brown and the fruit filling is bubbling up through the crust.
Cool for about 10 minutes and serve warm or chilled.