Slice and cube banana bread. Grease a deep dish pie pan or a round casserole dish. Spread half the cubed banana bread in the pie dish. Add sliced bananas. Cover with the other half of the cubed banana bread slices. Whisk milk, eggs, sugar, and vanilla in a medium-sized bowl. Pour over cubed banana bread and bananas. Using a spoon, squish the banana bread at the top down to make sure all of the pieces get into the creamy goodness. Let sit for about 10 minutes (or overnight) then bake at 350-degrees for about 45 minutes. (Cover the top for the last 15 minutes of baking.) Top with whipped cream.