- Heat olive oil in a large pot over medium heat. Add the onion, carrots, and bell pepper. Cook for 5–7 minutes, until veggies begin to soften. 
- Stir in the garlic and sauté for 1 minute, just until fragrant. 
- Add chili powder, cumin, smoked paprika, and oregano. Stir and cook for 30 seconds to toast the spices. 
- Mix in tomato paste and stir for another minute. Then pour in the crushed tomatoes and let simmer for 2–3 minutes. 
- Add the beans, corn, zucchini (if using), and broth. Stir to combine. 
- Bring to a boil, then reduce heat and let simmer uncovered for 25–30 minutes, stirring occasionally. 
- Finish with a splash of lime juice, adjust seasoning to taste, and remove from heat. Let sit for 5 minutes before serving.