Prepare soup from a packet of onion soup mix according to the package directions, and set 1 1/2 cups aside.
Place bacon grease into a large stainless steel soup pot over medium-high heat, and cook and stir the cubed round and sirloin steak meat in the bacon fat until well browned, about 10 minutes. Pour in the reserved onion soup, bring to a boil, then reduce to a simmer and cook for 7 minutes, stirring to dissolve any browned flavor bits from the pot.
Stir in salt, chili powder, cumin, black pepper, kidney beans, tomato paste, and tomato sauce. Bring the mixture to a boil, stirring frequently to avoid burning the bottom, then cover, reduce heat to low, and simmer for 1 hour, stirring occasionally. Stir in the cocoa powder, cola, and hot sauce, and simmer for 20 more minutes. Serve hot.