Preheat your oven to 375°F and generously grease a 9x9-inch baking dish.
In a large bowl, whisk together all the ingredients until combined. Pour into the prepared baking dish.
Bake for 35 minutes, or until set (if you move the pan, the oatmeal should not jiggle). Allow the oatmeal to cool for 5 minutes before slicing into squares. Enjoy!