Combine all ingredients, except steel cut oats, in a large pot on the stove. Over med-high heat, bring to a soft boil.
Stir in steel cut oats. Reduce heat, cover, and simmer for 20-25 minutes (stirring every 5-10 minutes) or until oats are tender.
Remove from heat and let sit covered for 5-10 minutes.
Serve immediately or portion out into your meal prep containers for the week. Top with your favorite toppings, a drizzle of maple syrup, and a splash of plant milk.
You can try making this in the oven for a more hands-free approach. Pre-heat oven to 350 degrees F (180 degrees C). Combine all the ingredients in a large bowl, mix well. Pour mixture into oven safe dish. Bake for 45-55 minutes. Let cool for 5-10 minutes before serving or portioning out into meal prep containers. I didn't try this but other followers have and it reportedly turned out well!