While the onion is cooking, use a food processor to finely chop the mushrooms. You can also use a knife to do this (it’s just faster and easier to get the mushrooms finely chopped with a food processor.)
Add the browned ground beef, the chopped mushrooms, chiles, diced tomatoes, tomato paste and all the spices to the pot with the onions.
Bring the chili to a boil, then reduce heat and cover. Simmer for about one hour, stirring occasionally.
After one hour you should taste the chili and adjust the salt and black pepper or even the chipotle peppers until you reach your own perfect level of chipotle chili taste.