Preheat the oven to 375 F and grease an 8x8 baking dish.
Heat a medium-sized skillet with 1 Tbsp butter on medium heat. Once hot, add the diced apples. Cook for about 5 minutes, stirring occasionally, then add ¼ cup water, 1 tsp pumpkin pie spice, and continue cooking until the apples are soft and the water has cooked out (about 5 more minutes). Once the apples are done, pour them into the bottom of the baking dish.
In a medium mixing bowl, combine the oats, remaining spices, baking powder, and sea salt, and mix until combined. Pour these evenly over the apples.
In the same bowl, stir together the milk, maple syrup, egg, and vanilla. Pour these on top of the dry ingredients and apples - make sure everything is distributed evenly. You may need to add a little more liquid if it does not reach the top of the oats.
Bake, uncovered, for about 40-45 minutes. Remove and allow to cool slightly before serving.
Top with whatever you like (suggestions above!) and serve warm. You can also store this for 3-4 days in the refrigerator for quick and easy breakfasts!
Recipe by Dana Monsees Nutrition at https://www.realfoodwithdana.com/spiced-apple-baked-oatmeal/