Heat the pot. Place a large, heavy pot or Dutch oven over medium heat. Add olive oil if using.
Brown the protein. Add ground turkey.
Cook 5–7 minutes, breaking it up with a spoon, until no pink remains and edges are lightly browned. Sprinkle with a pinch of salt.
Sauté aromatics. Add onion, garlic, and bell pepper. Cook 3–4 minutes until softened and fragrant.
Toast the spices. Stir in cumin, smoked paprika, chili powder, oregano, black pepper, and the 1/2 teaspoon salt.
Cook 30–45 seconds to bloom the spices.
Add grains and liquids. Stir in rinsed quinoa, black beans, diced tomatoes with their juices, and broth. Scrape the bottom to release any browned bits.
Simmer. Bring to a gentle boil, then reduce heat to low, cover, and cook 15–18 minutes, until quinoa is tender and uncurls. If using brown rice, simmer 35–40 minutes and add a splash more broth as needed.
Stir in greens. Fold in spinach.
Cover and cook 2 more minutes until wilted.
Finish. Turn off heat. Stir in lime juice. Taste and adjust salt, pepper, and chili powder.
If using cheese, sprinkle over the top, cover for 1–2 minutes, and let it melt.
Serve. Spoon into bowls and top with cilantro or green onions. Add a dollop of Greek yogurt or a few avocado slices if you like.