In a large heavy bottom pan or dutch oven over medium high heat, add the oil and ground beef and begin to brown the beef. Stir consistently with a wooden spoon to ensure the beef breaks up and no large chunks form.
After 3-4 minutes, add the onions and garlic.
Cook for another 1-2 minutes, then add the peppers and cook for another 1-2 minutes.
Once the peppers start to soften, add all of the beans and all of the spices, including the salt and pepper.
Mix and combine all the ingredients thoroughly and cook for 3-4 minutes.
Add the bottle of beer, do this carefully so the beer does not get too foamy, and simmer over the edge of your pot.
Mix everything well until the beer comes to a simmer, then turn the heat to medium and allow everything to simmer for another 2-3 minutes.
Add the crushed tomatoes and pumpkin puree, mix them in well, and turn the heat back up to medium high and bring the chili to a low boil.
Turn the heat down to medium low and allow the chili to simmer partially covered, and stirring occasionally for 30-45 minutes. If the mixture is too thick while simmering, add ½ to 1 cup of water as needed.
Salt and pepper to taste, and serve with fresh avocados, sour cream, and freshly chopped cilantro