In a large pot over medium heat, cook the ground turkey or beef until browned. Drain any excess fat.
Add the diced onion and minced garlic to the pot. Sauté for about 3-4 minutes until the onion is translucent.
Stir in the black beans, corn, diced tomatoes, and taco seasoning. Mix well to combine.
Pour in the chicken or vegetable broth and bring the mixture to a simmer. Cook for 10 minutes, stirring occasionally.
Reduce the heat to low and stir in the heavy cream or coconut milk. Allow the soup to heat through for another 5 minutes.
Add the shredded cheddar cheese and stir until melted and creamy. Season with salt and pepper to taste.
Serve hot, garnished with fresh cilantro and a dollop of sour cream if desired.