Pre-heat oven to 350 degrees F (175 C).
Peel, dice, and steam sweet potatoes for 10-12 minutes on medium high heat until you can easily poke with fork without sweet potato turning to mush (too mushy is no fun).
Add rolled oats to Vitamix and blend, starting on low speed and gradually increasing to high speed, until oats become a flour. Place flour in separate medium sized bowl.
To the flour, mix in the baking powder and cacao powder.
Place sweet potatoes in blender, along with Nutzo, maple syrup, and cinnamon and vanilla, if using. Blend on a medium speed until completely mixed and no sweet potato clumps remain.
Combine the sweet potato mixture with the flour mixture, and slowly add in plant milk as you stir to create your brownie batter.
Lightly grease an 8x12 baking dish with coconut oil, then put batter in dish and place in oven for 25-30 minutes, or until a toothpick comes out cleanly when poked in brownie. Enjoy with fresh berries and plant milk for a great start to your day!