Heat a tablespoon of olive or avocado oil in a large pot over medium-high heat. To the pot, add diced onion, carrots, bell pepper, and zucchini. Sauté the veggies for a few minutes to soften them, then stir in the minced garlic and cook until fragrant.
Add the tomato paste and sprinkle all the spices (chili powder, cumin, turmeric, smoked paprika, salt, black pepper, and optional cayenne pepper) over the veggies and stir to combine. Allow the mixture to cook for a minute or two more.
Stir in the remaining ingredients: vegetable broth, fire-roasted tomatoes, black beans, pinto beans, and ground flaxseeds. Bring the mixture to a boil. Turn down the heat and allow the chili to simmer covered for about 30 minutes (or until veggies are softened), stirring occasionally. (If it thickens too quickly, add a bit more vegetable broth or water until the desired consistency is achieved.)
Using a potato masher or immersion blender, mash or blend about one-third of the chili mixture. I do this step right in the pot. (This creates a thicker, heartier texture.)
Serve and enjoy with your favorite toppings! Our favorites include cilantro, vegan sour cream, green onion, jalapeño slices, or sliced avocado. For an added boost of protein and fiber, serve chili over cooked quinoa or brown rice.