Combine all ingredients, except toppings, in a small bowl or jar with a lid. I love using an almost empty jar of almond butter and the smaller mason jars.Cover and refrigerate overnight, or at least 4 hours.Enjoy cold or gently warmed in the microwave. Sprinkle with desired toppings and additional milk, as desired. I like to take my oatmeal out of the fridge about 10-20 minutes before I'm ready to eat. It's chilled, but not super cold.It works great to make several servings at once, to enjoy throughout the week. Prepared oatmeal cups will keep well for about 5 days in the fridge.