Heat the olive oil in a large, deep skillet over medium heat. Add the diced onion and red bell pepper, then cook for 4 to 5 minutes, stirring occasionally, until the vegetables begin to soften.

Add the minced garlic, cubed sweet potatoes, chili powder, cumin, smoked paprika, kosher salt, and black pepper. Stir continuously for about 1 minute so the garlic and spices become fragrant without browning too much.

Pour in the diced tomatoes with their juices and the vegetable broth. Stir well, scraping the bottom of the skillet to loosen any flavorful bits, and bring the mixture to a gentle simmer.

Cover the skillet and cook for 12 to 18 minutes, stirring occasionally, until the sweet potatoes are fork-tender. If the pan looks dry before the potatoes are cooked, add a small splash of vegetable broth.

Stir in the drained and rinsed black beans. Cook uncovered for 3 to 5 minutes, allowing the beans to heat through and the tomato mixture to thicken slightly.

Fold in the baby spinach, if using, and cook just until the leaves wilt into the skillet. Taste and add more salt if needed.

Remove the skillet from the heat and finish with chopped cilantro and a squeeze of lime juice. Serve hot with the remaining lime wedges for individual seasoning.