Heat the oil in a large heavy-bottomed pot over medium heat until shimmering and fragrant.
Add the diced onion and cook, stirring occasionally, until it becomes translucent and starts to soften, about 5 minutes. You should smell a sweet aroma and see the onions turn slightly glossy.
Stir in the minced garlic, sliced carrots, and sliced celery. Cook for another 8 minutes, stirring occasionally, until the vegetables are tender and fragrant, and the mixture begins to look glossy and colorful.
Add the smoked paprika, cumin, and chili powder, stirring constantly for 30 seconds until the spices release their warm, earthy aroma. Be careful not to burn the spices—this helps deepen the flavor.
Pour in the vegetable broth, scraping the bottom of the pot to loosen any browned bits—these add great flavor. Bring the mixture to a gentle simmer, with small bubbles breaking the surface.
Stir in the rinsed and drained black beans, then lower the heat to medium-low. Cover the pot partially and simmer for 20 minutes, allowing the flavors to meld and the stew to thicken slightly.
Uncover and taste the stew, adding salt if needed. Finish with a squeeze of lemon juice or a dash of vinegar to brighten the flavors. Stir well and let rest for a few minutes to deepen the taste.
Serve hot, garnished with fresh herbs if desired. Enjoy this thick, smoky, and satisfying vegan stew that feels like a comforting hug in a bowl.