01 - If using ground beef or sausage, heat a skillet over medium heat and cook the meat until fully browned, breaking it apart with a spoon. Drain off any excess fat and set aside.
02 - Add the cubed processed cheese, cubed cream cheese, and the entire can of Rotel diced tomatoes with green chilies (including the juices) into the slow cooker. If using the cooked meat, add it now as well.
03 - Sprinkle in the garlic powder and black pepper evenly over the top of the ingredients in the crockpot.
04 - Cover the crockpot and cook on the low setting for 2 hours, stirring every 30 minutes or so, until all the cheese has fully melted and the dip is smooth and creamy throughout.
05 - Leave the crockpot on the warm setting and serve the dip directly from it alongside tortilla chips, crackers, or fresh vegetable sticks.