Combine all ingredients in a Mason jar or Tupperware container. Stir, close lid, and shake until well-combined. Refrigerate overnight, or at least 6 hours.
Stir again, and add 1 to 2 Tbsp. extra Tablespoons of milk to loosen up, if needed. Add toppings of choice (fresh fruit, peanut butter drizzle, walnuts, etc.)
Notes
Store covered in the refrigerator for up to 4 days.