Heat olive oil in a large pot over medium heat. Add diced onion and cook for 3-4 minutes until softened and fragrant, stirring occasionally to prevent browning. This creates the flavor foundation for everything that follows.

Add minced garlic to the pot and stir constantly for 30-45 seconds until the aroma becomes strong and inviting. Don't let garlic brown, as it becomes bitter and overpowers the dish. The moment it turns golden, move to the next step.

Pour in drained black beans, diced tomatoes with their juice, and vegetable broth. Add cumin, chili powder, salt, and black pepper, stirring to combine all ingredients thoroughly. Bring the mixture to a gentle simmer over medium heat.

Add diced red bell pepper and corn to the pot. Simmer for 12-15 minutes, stirring occasionally, until the bell pepper becomes tender and the broth reduces slightly. This is when your cozy black bean weeknight recipe truly comes together, with flavors melding beautifully.

Stir in fresh spinach and cook for 2-3 minutes until completely wilted. Remove from heat and squeeze fresh lime juice over the entire pot, then scatter cilantro on top. Taste and adjust seasonings as needed—some prefer extra salt or lime juice.