Combine the oats, water, and salt in a jar: Use ½ cup of water for thick, spoonable oatmeal, or ¾ cup for a softer, more porridge-like oatmeal. (You can also stir in additional liquid later on to thin it out, so no need to add too much here.) Secure the lid and swirl the contents a few times so that the oats are soaked.

Pack up your toppings: Combine a handful of chosen oatmeal toppings in a small container. (If you're making multiple servings for breakfasts during the week, wait to assemble the toppings until the night before you plan to eat the oatmeal.)

Refrigerate overnight or up to 5 days.

Microwave the oatmeal: Remove the lid from the container and set aside. If desired, transfer the oats and their soaking liquid to a separate microwave-safe bowl. Place the container on a microwave-safe plate (to catch any accidental spills), and place in the microwave. Microwave on high power for 30 seconds, then remove the oatmeal and stir. Microwave for another 30 seconds, then remove and stir again. If the liquid is not quite piping hot, microwave for another 15 to 30 seconds, or as needed until the liquid is very hot. Cooking time may vary from microwave to microwave; in my microwave, 1 minute and 20 seconds total cooking time was perfect. At this point, the oats probably won't quite look like oatmeal yet; there will still be a thin layer of foamy liquid on top of the oats. This is ok.

Let the oats stand for 2 to 3 minutes to thicken: After letting them stand a few minutes, give the oats a stir. The oatmeal should become thick and creamy as you stir. If it still seems more liquidy than you'd like, microwave for another 15 to 30 seconds, but be very watchful for foaming liquid . If the oats seem too stiff and thick, stir in splash of milk, water, or other liquid to loosen them up again.

Stir in toppings and serve. Enjoy!