01 - Heat olive oil in a large pot or Dutch oven over medium heat. Add the diced onion and red bell pepper and cook until softened, about 5-7 minutes. Stir in the minced garlic, chili powder, cumin, and smoked paprika, and cook for 1 minute until fragrant.
02 - Add the minced chipotle peppers in adobo sauce, black beans, crushed tomatoes, pumpkin puree, and vegetable broth to the pot. Stir well to combine all ingredients.
03 - Bring the chili to a simmer, then reduce heat to low. Cover and cook for 20-30 minutes, stirring occasionally, until the chili has thickened to your desired consistency. For a thicker chili, remove the lid during the last 10 minutes of simmering.
04 - Taste the chili and season with salt, freshly ground black pepper, and additional chipotle peppers if desired for more heat.
05 - Ladle the chili into bowls and serve hot, garnished with lime wedges, a dollop of sour cream or Greek yogurt, and chopped fresh cilantro.