2 Tablespoons olive oil
Coarse salt and ground pepper
2 medium sweet potatoes (about 1 pound total), peeled and cut into 3/4-inch cubes
1/4 teaspoon red-pepper flakes - optional but I recommend. It's good with the lime!
2 tablespoons fresh lime juice (from 1 lime), plus wedges for serving
1 can (14 1/2 ounces) black beans, rinsed and drained
1/2 medium red onion, finely chopped - I added too much this time. 1/4 onion is more appropriate
1/2 cup chopped fresh cilantro - I didn't use any this time but I highly recommend it!
Place sweet potatoes on a foil lined rimmed baking sheet; drizzle with oil. Season with red-pepper flakes (if using), salt, and pepper; toss to coat. Roast on lower rack, until tender, tossing once during cooking, 25 to 35 minutes.
In a large bowl, whisk lime juice with remaining 2 tablespoons oil; season with salt and pepper. Add sweet potatoes, beans, onion, and, if using, cilantro; mix gently to combine.