1. Preheat oven to 400 degrees Fahrenheit. Add sweet potatoes and bake until soft throughout, about 45 minutes. Peel and mash with beans.
2. Heat oil in a sauté pan over medium heat. Add onion and sauté until soft, five to seven minutes. Add garlic and cook an additional two minutes.
3. Add onion mixture, brown rice, cumin, chili powder, parsley, egg, bread crumbs, salt, and pepper to sweet potato mixture. Form mixture into patties and refrigerate for at least 20 minutes.
4. Heat olive oil in a frying pan. When hot, add patties and fry until golden.
5. Assemble sandwiches. Spread each burger with one tablespoon garlic aioli. Serve on a toasted bun with a slice of cheese.
I use the garlic aioli, first featured in Whisk Issue #217 on the garlic aioli roast, as a spread for these burgers. In a tall, wide glass or container, combine six garlic cloves, two tablespoons vinegar, two eggs, 1/4 teaspoon sugar, 3/4 teaspoon salt, and 1/2 teaspoon pepper. With a hand blender, blend until mixture starts to get frothy. Slowly add 1 and 1/2 cups canola oil and blend until mixture forms into mayonnaise texture. Mixture will thicken once it is refrigerated.