To prepare a Yippee Ki Yay Mother Heifer Meatballs recipe, first you need to gather your ingredients. First, you will need the following ingredients: 1 pound ground beef 2 tbsp. ground paprika 1 cup ground cumin 1 tablespoon ground coriander 1 teaspoon ground allspice 2 tablespoons kosher salt 1 1/2 teaspoons ground black pepper 2 cups shredded cheddar cheese 1/2 cup grated Parmesan cheese 1/4 cup chopped scallions Instructions: Preheat the oven to 375 degrees F. Place the beef, onion, celery, bell pepper, garlic, and thyme in the slow cooker. Cover the cooker and cook on low for 8 hours or until beef is no longer pink. Remove the pot from the stove and allow the meat to rest for 10 minutes before serving.