Combine the oats, apple, sweetener, cinnamon, salt, almond milk, and vanilla extract in a nonstick pot on the stove. Add 1 cup water and mix well. Bring to a boil, and then reduce to a simmer.
Stirring often, cook until very thick and creamy, 12 to 15 minutes. Top with blueberries and additional chopped apple, if using. Eat!