Set your oven to broil and arrange the chiles on a baking sheet. Broil, turning often, until the skin is evenly charred but not burnt. Once roasted, cover with a dish towel for 10 minutes to steam, which makes peeling easier.

While the chiles rest, heat vegetable oil in a large pot over medium-high heat. Season cubed pork shoulder with salt and pepper, then add to the pot along with onions and garlic. Sauté for about 5 minutes until the pork begins to brown and the onions turn translucent.

Add the diced jalapeños (if using), chicken broth, half the can of beer, oregano, salt, pepper, bay leaves, and cumin. Bring to a simmer over medium heat, then reduce to low and let simmer gently for 1 hour.

Once steamed, peel the skins from the chiles, remove stems, and chop. For a spicier stew, keep the seeds; for a milder version, remove them. Add the chopped chiles to the pot and stir well.

Simmer the stew for another 30 minutes, then add the diced tomatoes and potatoes. If the broth is too thick, add a cup of hot water to maintain a soupy consistency. Continue cooking until the potatoes are tender, about 20–25 minutes.

In a small skillet, melt butter over medium heat. Add flour and cook, stirring constantly, for about 2 minutes to form a roux. Whisk the roux into the stew to slightly thicken the broth, giving it a richer texture.

Remove the bay leaves, taste for seasoning, and adjust as needed. Serve steaming hot with warm flour tortillas, corn tortillas, or cornbread on the side.