Heat 1 tablespoon of the reserved bacon drippings in the dutch oven over medium-high heat. Add the onion and bell pepper and cook for 5 minutes. Add the garlic, chili powder, cumin, paprika, oregano and tomato paste and cook for 6 minutes (add a splash of water if the mixture begins to stick). Add the beer and simmer until almost completely reduced, about 3 minutes. Stir in the beef and any juices from the plate; add the cocoa powder, tomatoes, beef broth and beans and bring to a simmer. Cook, stirring occasionally, until the chili thickens slightly, about 90 minutes.