In a Dutch oven, melt the butter over medium heat.
Add the onions and green peppers to the pot and cook for 5 minutes, until soft and translucent. Add the garlic and cook another 2 minutes, until the garlic is warm and fragrant.
Add the chili powder, cumin, oregano, and salt. Cook for 1 minute, stirring, until the vegetables are glistening and dark brown.
Add the beer, scraping up any bits that are stuck to the pot. Bring to a low boil and allow the beer to reduce by half.
Add all the remaining ingredients and stir to combine.
Allow to simmer another 10-30 minutes, so the flavors combine.
Serve with toppings as desired.