Heat 2 tablespoons oil in a 6-qt. pot over high heat and sauté ground seitan 'til slightly browned. Remove with slotted spoon and set aside. Add 1 tablespoon oil and sauté mushrooms 'til browned; remove with slotted spoon and set aside.
Heat 1 more tablespoon oil, then add onions and garlic; cook until lightly browned, about 5 minutes. Return ground seitan to pot; stir in tomato paste. Cook, stirring frequently and scraping bottom of pot with a wooden spoon, until tomato paste is caramelized, about 12 minutes. Add oregano, chili powder, chile pequín, paprika, tabasco, and cumin; cook, stirring frequently, for 1 minute.
Add broth or water, beer, mushrooms, and chipotle peppers; bring to a boil. Reduce heat to medium-low; simmer, stirring occasionally, about 2 hours. Stir in masa harina; season with salt. Simmer, stirring, until thickened, about 5 minutes.
Recipe Notes
Serve with chopped white onions, jalapeños, and chopped cilantro.