This casserole can go from breakfast, to brunch, to dessert. It is just that versatile.
Whisk the egg, milk, vanilla and cinnamon together in a medium bowl. Cut each piece of bread on the diagonal and dip into the egg mixture. Place in a 7 x 11 casserole dish that has been sprayed with cooking spray. You will need to overlap the half pieces of bread. Spread the pie filling evenly on top of the bread.
To make the streusel topping, combine the oatmeal, flour and brown sugar in a medium bowl. Cut in the butter with a pastry blender or two knives. Sprinkle over the pie filling.
Bake in a preheated 350 degree oven for 40 minutes. Cool until ready to serve.