Preheat the oven to 350 °F and prepare two muffin tins. The recipe makes 16-18 cups so you need more than one tin. *I recommend using silicone liners if possible as these cups tend to stick a bit to paper liners. If you don't have silicone liners, you can bake them right in the muffin tin but be sure to grease it very well.
In a large bowl, mix together all of the ingredients except for the add ins until well combined. Fold in add-ins (if using).
Scoop the batter evenly into your prepared muffin tin, filling all the way to the top.
Bake for 27-30 minutes until the centers are set (they should bounce back slightly when pressed).
Remove from the oven and allow to cool for 10 minutes in the muffin tin.
If you baked them directly in the muffin tin, run a butter knife around the edges of each to help release them.
Enjoy warm or move to a wire rack to cool completely.
Notes
LeftoversLeftover baked oatmeal cups can be stored at room temperature for up to 1 day, in the refrigerator for up to 4 days or frozen for up to 3 months.Enjoy cold or reheat in the microwave or oven at 350 F for 4-5 minutes.*I have also tested this recipe with brown rice protein powder and a combination of rice and pea protein- all worked well. You can try this recipe with your favorite protein powder but know that different powders absorb different amounts of liquid so the texture may vary. You can experiment with adding 1-2 tablespoons less water if using an animal-based protein powder.**Nutrition calculated for base recipe using almond butter as the nut butter and 2 cups of mixed berries as the add in.