In a large mixing bowl, combine dry ingredients (oats, brown sugar, cinnamon, baking powder, salt). Stir to combine, chopping up any lumps of brown sugar.
Beat in milk, eggs, melted butter and vanilla.
Spread into well greased 9x13 inch pan.
In a small bowl, mix together bananas foster mix in ingredients (diced bananas, brown sugar, melted butter, rum).
Spoon bananas foster mixture over oatmeal mixture.
Bake for 40 minutes. Allow to cool for a few minutes before slicing.