Heat a large heavy-bottomed pot over medium heat. Add a splash of oil, then toss in the chopped onion and bell pepper. Cook, stirring occasionally, until they soften and become fragrant, about 5-7 minutes, with the onions turning translucent.
Add the minced garlic along with cumin and smoked paprika. Stir constantly for about 1 minute until the spices are toasted and fragrant, filling the kitchen with a smoky aroma.
Pour in the canned diced tomatoes and vegetable broth, stirring to combine all the ingredients. Bring the mixture to a gentle simmer, then reduce the heat to low. Let it cook uncovered for about 10 minutes, allowing the flavors to meld and the sauce to thicken slightly.
Add the rinsed and drained black beans to the pot. Stir well and continue simmering for another 10 minutes, until the beans are heated through and the sauce has thickened to a hearty consistency.
Taste the chili and season with salt and pepper as needed. If desired, squeeze in a little lime or add hot sauce for extra brightness and heat.
Remove the chili from heat and let it sit for 5 minutes. This rest period allows the flavors to deepen and develop. Serve hot, garnished with fresh herbs or avocado if you like.