You can whip up a batch of this oatmeal on the weekend and have it for breakfast for the rest of the week. It's great reheated from the fridge or freezer and I love it topped with some warm milk, Greek yogurt, and berries.
Preheat your oven to 375 degrees and spray an 8 x 8 pyrex with cooking spray.
Combine oats, ground flax, brown sugar, cinnamon, pumpkin pie spice, salt, baking powder, and cranberries in a large bowl.
In a separate bowl, whisk together milk, pumpkin puree, butter, egg, and vanilla. Add wet mixture to dry and combine. Stir in apples.
Spread oatmeal mixture evenly into pyrex and top with chopped walnuts. Bake for about 20 minutes, or until the oatmeal is set and slightly browned on top. Serve warm topped with yogurt or milk.