Rinse and chop leek, onion, peppers and mushrooms.
In large oven proof pot melt bacon fat or heat oil. Add chopped vegetables and saute until soft but not brown.
Mince garlic. Add to vegetable mixture, along with beef and pork and cook until meat is browned.
Drain beans, rinse well and drain. Add to meat mixture.
If desired, arrange chopped tomatoes on a large baking sheet and roast for approximately 20 minutes until liquid is reduced. Otherwise, simply add chopped tomatoes to meat mixture and bring to a simmer. Add crushed tomatoes, tomato paste and Worcestershire. Stir in cumin, chili powder, cayenne, cocoa powder and salt and pepper. Taste to ensure desirable amount of salt.
Preheat oven to 350 degrees.
Add can of beer to chili. Bring to a simmer. Cover and bake in oven for at least one hour.
If desired, garnish with any combination of sour cream, minced green onion and shredded cheddar cheese.