Chop apples into hearty chunks (leave skins on).
Add 4 cups of filtered water to a pot. Stir in the apples, vanilla, apple pie spice, and sea salt. (Add in the raisins or cranberries if desired). Bring to a boil.
Once the water is boiling, stir in 2 cups of oats. Stir well to prevent the oats from bubbling over.
Turn the heat down to medium-low. Cover with a lid, and simmer for 10 minutes until the oats have thickened.
Top each serving with a pat of butter, brown sugar or maple syrup, and walnuts or pumpkin seeds.