In a heavy 6-quart pot, heat the oil over medium-high heat. Add the onions, garlic, chili powder, Essence, salt, cumin, and black pepper, and cook, stirring, until soft, 4 minutes. Add the meat and stir with a large wooden spoon to break it up. Cook, stirring, until the meat is brown and cooked through, 5 minutes. Add the tomatoes, tomato paste, sugar, and beef stock. Stir well and bring to a boil. Lower the heat to medium-low and simmer uncovered for 50 to 55 minutes. Stir in cheese if using. Keep warm until ready to serve.
Yield: 6 cups (about 6 to 8 servings)