Combine all ingredients except vanilla extract and flax meal in a crockpot. Stir to combine. Turn to low heat, cover and cook for 4-7 hours. Shorter time will mean a chewier oatmeal and longer will be creamier.
At the end of cooking, stir in vanilla extract and flax meal, if using. Serve immediately, or store in a glass container (if using plastic, cool completely first) to eat throughout the week. I like to portion mine individually into small glass jars.
REHEATING INSTRUCTIONS: Add a serving of oatmeal to a small pot, along with 1/2 cup water. Cook on medium-low heat, stirring, until oatmeal is creamy and warmed through. Add more water to taste. Topping suggestions: raisins, dried chopped apple rings, almond butter, extra cinnamon, toasted coconut flakes, chia seeds