Stem and seed the ancho chiles and place in a pot with stock, bring the mixture to a boil then reduce the heat and keep warm.
Heat a Dutch oven over medium-high heat with 1/4 cup extra-virgin olive oil, 4 turns of the pan. Add the mushrooms to the hot oil and brown 12 to 15 minutes, then add the garlic, onions, chile, salt and black pepper and soften 5 to 6 minutes more, season with a spice mixture of paprika, cumin, coriander, and cinnamon.
Puree the reconstituted chiles and stock in a food processor. Add the chile stock mixture, beans, and tomatoes to the chili, cook 15 minutes until thickened, then turn off the heat, cool, cover and chill for make-ahead meal.
To reheat: Cover the chili and place over medium to medium-high heat, stirring frequently until the chili bubbles, then uncover and simmer until ready to serve.
Combine the avocado, sour cream, lime juice, cilantro, and salt in food processor and process into a smooth avocado-sour cream sauce for stirring into the chili. Serve the chili in shallow bowls and garnish with the avocado sauce, pepitas, if using, and a few tortilla chips, if using.