Preheat the oven to 400 degrees F. Scrub and wash the sweet potato, and then poke several holes in it with a fork. Place the potato on a piece of aluminum foil on the center rack of the oven, and cook for 45-60 minutes or until tender. (You can do this up to a few days in advance or instead make a Microwave Sweet Potato to save yourself a ton of time.) Remove from the oven, and decrease the oven temp to 375 degrees F. Spray a baking sheet generously with oil or line with parchment paper, and set aside.
Combine the sweet potato flesh, black beans, onion, bread crumbs, parsley, and garlic in a large bowl. Use your hands, a potato masher, or a large spoon to mix until well combined.
Add the cumin, salt, pepper, apple cider vinegar, and lime. Mix until well combined.
Use your hands to form the batter into 8 patties. Place each burger on the baking sheet and cook for 25 minutes, flipping halfway through.
Enjoy! Serve on a bun or lettuce leaf with toppings.
Storage: The burgers will last in an airtight container in the fridge for up to 5 days.Freezing and reheating: To freeze, let the burgers cool and then transfer to a lined baking sheet. Place the baking sheet in the freezer for 1-2 hours. Once the burgers are frozen, transfer to a plastic bag or airtight container to keep in the freezer. Reheat on high in the microwave for ~1 minutes.Make gluten free: Sub ground gluten free oats for breadcrumbs.