Preheat oven to 425°F (220°C). Toss ½ inch cubed sweet potatoes with 1 tablespoon olive oil. Spread evenly on a sheet pan and roast 25-30 minutes until tender with golden edges. Check doneness by piercing with a fork; it should slide in easily but cubes hold their shape.
2 medium sweet potatoes, 2 tbsp olive oil
Heat remaining 1 tablespoon olive oil in a large skillet over medium heat. Add diced onion and cook 5 minutes until soft and translucent. Add minced garlic and toasted ground cumin, cook 1 minute until fragrant. Remove from heat.
1 medium onion, 3 cloves garlic, 1 tsp ground cumin, 2 tbsp olive oil
Add the roasted sweet potatoes and drained black beans to the skillet with the aromatics. Roughly mash with a fork or potato masher, leaving some chunks for texture. Season with salt and pepper to taste.
2 medium sweet potatoes, 15 oz black beans, 1 medium onion, 3 cloves garlic
Spread ½ cup enchilada sauce evenly on the bottom of a 9x13 inch baking dish. Wrap corn tortillas in a damp towel and microwave for 30 seconds to soften.
12 count corn tortillas, 2 cups enchilada sauce
Spoon about ⅓ cup of filling along the center of each warmed tortilla. Roll tortillas tightly and place seam-side down in the baking dish. Pour remaining enchilada sauce evenly over the enchiladas and sprinkle with shredded cheese if using.
12 count corn tortillas, 2 cups enchilada sauce, 1 cup shredded cheese
Cover the dish tightly with foil and bake at 375°F (190°C) for 20 minutes. Remove foil and bake uncovered for an additional 10 minutes until sauce is bubbly and edges are slightly crisp. Let rest for 5 minutes before serving.
