Mix together the oats, almond milk, sweetener, salt, and cinnamon in a microwave-safe bowl. Make sure your bowl is extra large for the boil over that happens when you make oatmeal in the microwave.
Stir in the chopped apple (this works best if the apple is peeled but you can leave the peel on).
Microwave for 2.5-3 minutes (if you use steel-cut oats, you may need a bit longer based on the power of your microwave.
Remove from heat and check the oats are done. If you use steel-cut, you may need another minute.
Dilute with more almond milk to get desired consistency. Crush the graham cracker over the top and enjoy!
Stovetop Option
Mix all ingredients together (except the graham cracker) in a saucepan.
Bring to a boil, then reduce to a simmer for 5-8 minutes. The cook time depends on the type of oats you use (quick cooking, old fashioned and rolled will take just a few minutes, steel-cut will be more like 8-10 minutes).
Remove from heat when oats are done (taste them to ensure the texture of oat is good) and the consistency is at desired level. If they get too thick, you can stir in more milk.