Big Game Day Chili

2 tablespoons vegetable oil

2 yellow onions, chopped

1 sweet onion, chopped

1 head garlic, peeled and minced

1 yellow bell pepper, chopped

1 orange bell pepper, chopped

2 pounds cubed beef stew meat

2 pounds Italian sausage meat

4 slices applewood smoked bacon, cut into 1-inch pieces

2 (28 ounce) cans tomato sauce

2 (6 ounce) cans tomato paste

2 (14 ounce) cans black beans, rinsed and drained

2 (14.5 ounce) cans kidney beans, rinsed and drained

1 (7 ounce) can chipotle peppers in adobo sauce, chopped

2 cups beef broth

1 (12 fluid ounce) bottle dark beer

¼ teaspoon chili powder, or to taste

¼ cup crumbled dried oregano

1 tablespoon fresh-ground black pepper

2 teaspoons salt, or amount to taste

2 ½ ounces dark chocolate candy bar