Make the barbecue sauce first by heat beef broth on the stovetop until it’s simmering. Add tomato paste to the broth, and stir over low heat until the tomato paste heats through and blends with the broth. Next, stir worcestershire sauce, liquid stevia, onion powder, thyme, and pepper into the sauce. Cover the pot and let the ingredients heat until simmering again. Then, add butter to the sauce and stir until melted.
Let the sauce bubble over low heat until it reduces and thickens slightly – about 10 minutes. Remove the lid, turn the heat up slightly, and let the sauce continue bubbling until it reduces to a “stew-like” thickness. Set the sauce aside to cool and set a little. Don’t worry, the sauce will have time to thicken more later in the recipe.
In a large mixing bowl, combine ground beef with mayonnaise, parmesan cheese, seasoned salt, pepper, mustard powder, cumin, paprika, and garlic powder. Once the mixture is blended into an even, pale pink mixture, you can form the meatballs. Divide the meat into 2-tablespoon portions, and roll each portion into a meatball. Heat the olive oil in a large sautee pan over high heat. Once the oil is hot, arrange all the meatballs inside the pan to start cooking.
Let the meatballs cook on one side until they are charred – about 3-4 minutes. Reduce the heat to a medium temperature, and rotate the meatballs to another side. Continue cooking until the meatballs are charred on all sides, but they do not have to be cooked through yet. Reduce the heat to a low temperature, and pour your prepared barbecue sauce into the pan. Gently rotate the meatballs in the sauce, then cover the pan with a lid.
Let the meatballs stew in the sauce while it bubbles for several minutes. When you see the sauce has reduced a little more, remove the lid from the pan. Continue cooking openly on the stove, rotating the meatballs, until the sauce is thick enough to stick to the meatballs and is at your desired thickness. At your discretion, you can include other ingredients to add more calories to your meal.