1Preheat your oven to 375°F (190°C).
Peel and grate the sweet potato, potato, and carrot.
Finely chop the onion.
In a large bowl, combine the grated sweet potato, potato, carrot, and chopped onion.
Add the quick oats, nutritional yeast flakes, flaxseed, garlic powder, and sage to the bowl.
Mix all the ingredients thoroughly until well combined.
Form the mixture into patties of your desired size.
Heat the olive oil in a large skillet over medium heat.
Cook the patties in the skillet for about 3-4 minutes on each side, until they are golden brown.
Transfer the patties to a baking sheet and bake in the preheated oven for 15-20 minutes, until they are cooked through.
Remove from the oven and let them cool slightly before serving.