Combine apple and brown sugar in a small bowl. Mix well.
Microwave apples for one minute, then stir. Cook for another 30 seconds, or until apples are softened and tender.
Add half the apples, along with the oats, milk, half the walnuts, maple syrup, cinnamon, vanilla, and salt, to a mason jar. Mix well.
Top oats with remaining apples and walnuts. Cover and refrigerate overnight, or for at least 4 hours, before eating. Enjoy!
I recommend using crisp, tart-sweet apples, like Fuji, Gala, Pink Lady, or Honey Crisp (which is what I used) for this recipe.Any kind of milk works here, although 2% or whole will give you the creamiest results.To make the recipe vegan, use a vegan brown sugar and any kind of non-dairy milk, such as almond milk. I used soy milk, which worked great.Check out the info before the recipe for more tips and variations.