For Overnight Oats:
In a large container with a tight-fitting lid, add all the oatmeal ingredients and stir well. Seal and place in the refrigerator overnight, or at least for 6 hours.
For the hot, quick version:
In a medium sauce pan, add everything EXCEPT the vanilla extract, heat over medium-high heat.
Bring to a full boil, then reduce heat and simmer 15 to 30 minutes, stirring occasionally until oatmeal has thickened and the liquid has been mostly absorbed.
Remove from heat and stir in vanilla extract.
Divide between four bowls and top with garnishes, as desired.
For heating the overnight oatmeal:
Using your preferred method, either:
Place oatmeal in a medium sauce pan and heat over low heat, stirring occasionally until oatmeal is to desired temperature. If oatmeal becomes too dry, add more coconut milk till desired consistency is reached. Don't add too much because you want it thick and you can always add more milk during garnish. Or,
Place oatmeal in a microwave-safe dish and heat on high for 30 second intervals until desired heat is reached.