Preheat oven to 350 degrees. Butter an 8 by 8-inch baking dish, set aside.In a large mixing bowl whisk together eggs. Add in brown sugar, baking powder, cinnamon, vanilla and salt and whisk until no lumps remain. Stir in milk and melted butter then mix in oats. Pour into prepared baking dish and spread evenly (at this point you can refrigerate overnight if desired or bake immediately). Bake in preheated oven 30 - 40 minutes until set.Cut into squares and serve warm with fresh fruit, nuts, milk, a little cream or half and half, maple syrup or honey if desired.Recipe source: adapted slightly from food.com