Prep the vegetables. Peel and cube the sweet potatoes. Dice the onion and bell pepper, mince the garlic, and prep the jalapeño if using.
Keep the pieces small and uniform for even cooking.
Optional sauté for deeper flavor. In a skillet, warm the olive oil over medium heat. Sauté the onion and bell pepper for 4–5 minutes until softened. Add the garlic and spices (cumin, smoked paprika, chili powder, coriander) and cook 30 seconds, just until fragrant.
This step is optional but adds richness.
Load the slow cooker. Add sweet potatoes, black beans, diced tomatoes with juices, sautéed vegetables (if using), tomato paste, bay leaf, salt, pepper, and broth to the crockpot. Stir to combine and make sure the tomato paste dissolves.
Set and cook. Cook on Low for 6–8 hours or High for 3–4 hours, until the sweet potatoes are tender and starting to break down.
Finish and adjust. Remove the bay leaf. Stir in the lime juice and cilantro.
If the stew is too thick, add a splash of broth. If it’s too thin, mash some sweet potatoes against the side of the pot to thicken.
Taste and serve. Adjust salt, pepper, and lime to taste. Ladle into bowls and top with avocado, yogurt, green onions, tortilla chips, or cheese as you like.