1. Place a small sweet potato on a baking pan and bake at 400 degrees for about 45 minutes. If you're short on time, you can microwave it for 6 minutes (baking yields a bolder flavor).
2. If you don't have brown rice on hand, cook some up, or use one of the DIY brown rice freezer packs [1] you have on hand. If you ran out like I did, use something like the frozen rice medley from Trader Joe's.
3. In a food processor, process the onion until finely chopped. Add the beans and pulse until coarsely chopped (don't puree).
4. Spoon the onion and bean mixture into a mixing bowl. Add the sweet potato, cooked rice, nutritional yeast, garlic powder, and salt. Mix well.
5. Place a cast-iron pan on medium heat. Add the oil. Take large spoonfuls of the veggie burger batter and form into 4 quarter-inch-thick patties. Use the back of your spoon to flatten and round out the edges. If your pan is small, cook 2 at a time. If your pan is large, cook all 4 at the same time.
6. Cook these patties slowly so as not to burn them. Brown each side for about 5 or more minutes. Carefully flip and brown the other side.
7. Serve on a whole-wheat bun with whatever toppings you choose. I used lettuce, tomato, and avocado.

Source: Calorie Count [2]

The calorie count above is for the patty only. But here's the calorie count for a patty with a bun and all the fixings:

Whole-wheat bun (120 calories [3])
1 leaf of lettuce (1 calorie [4])
2 slices of tomato (8 calories [5])
1/4 avocado (80 calories [6]

Total calories: 365