Step 1: Cook the ground beef in a large pot over medium heat, breaking it up with a spoon. Cook for 5-7 minutes, or until browned and fully cooked. Drain any excess fat.
Step 2: Add the chopped onion and minced garlic to the pot. Cook for 3-4 minutes, until the onion softens.
Step 3: Stir in chili powder, cumin, paprika, salt, and pepper. Cook for about 1 minute, stirring constantly, to toast the spices.
Step 4: Add the red enchilada sauce, diced tomatoes, kidney beans, black beans, and beef broth to the pot. Stir to combine. Bring to a simmer over medium heat and cook for about 15-20 minutes, stirring occasionally.
Step 5: Stir in 1 1/2 cups of shredded cheddar cheese until melted completely. If chili is too thick, add a splash more beef broth or water.
Step 6: Taste and adjust seasoning (salt, pepper, chili powder, paprika, or cayenne pepper for spice) if necessary.
Step 7: Spoon into bowls, top with the remaining 1/2 cup shredded cheddar cheese, a dollop of sour cream (optional), and fresh cilantro (optional). Serve hot with tortilla chips, cornbread, or a side salad.