Heat a comal or large griddle to medium heat. Add the tomatoes, garlic(with skins on), onion and serrano peppers. Dry roast for 20-25 minutes, turning as needed. Remove the garlic after 15 minutes and set aside.
When ready, to the blender, add the tomatoes, peeled garlic, onion, serranos, beef broth, beer, cinnamon, cumin, oregano, thyme, marjoram, salt and pepper. Pulse to blend to achieve a coarse salsa. Set aside.
Add two tablespoons of butter and two tablespoons of oil to a large pot and heat to medium. As soon as the butter melts, add the sliced beef. Season lightly with salt and pepper. Cook until beef is browned all around and begins to release it's juices. Add the flour and stir well to combine. Continue stirring for 1-2 minutes to cook out the raw flavors of the flour.
To the pot, pour in the salsa from the blender and the bay leaves. Stir well to combine. When it comes up to a simmer, taste for salt. Cover and reduce heat to below medium. Cook for 25 minutes. Add in the potatoes and continue cooking for 25 minutes or until beef is tender. Fold in the peas and cook for 2-3 more minutes.
Serve with Mexican rice, beans and warm tortillas. Yields 6-7 servings.