Begin by chopping the onion and bell pepper into small, even pieces. This helps them cook uniformly and meld flavors beautifully.
Heat the slow cooker and add a splash of olive oil, then sauté the chopped onion and bell pepper until they soften and become fragrant, about 3–4 minutes.
Add the minced garlic, cumin, and smoked paprika to the vegetables and cook for another minute until aromatic. Stir well to coat everything evenly.
Pour in the diced tomatoes with their juice, stirring to combine all the ingredients. This creates a flavorful base for the chili.
Add the drained beans to the mixture, stirring gently so they are evenly distributed without breaking apart.
Season with salt and pepper to taste, then cover the slow cooker with its lid. Set it to low and let it simmer for 4 hours, allowing the flavors to deepen and the vegetables to become tender.
After the cooking time has elapsed, remove the lid and give the chili a gentle stir. Check the seasoning and adjust with more salt, pepper, or spices if needed.
Serve the hearty vegetarian chili hot, garnished with your favorite toppings like chopped cilantro, shredded cheese, or a squeeze of lime to brighten the flavors.