15 dried guajillo chiles (available at marxfoods.com)
1 clove garlic
1⁄2 small white onion, roughly chopped
2 1⁄4 lb. Yukon gold potatoes, peeled and cut into 1⁄2” cubes
Kosher salt, to taste
1⁄2 cup canola oil
1 1⁄4 lb. fresh chorizo, casings removed
6 soft pambazos, teleras (see Mexico’s Daily Breads), or kaiser rolls, split
3 shredded iceberg lettuce
2 cups grated queso Oaxaca (available at mexgrocer.com) or mozzarella
3⁄4 cup crema (available at mexgrocer.com) or sour cream
Heat a 12″ skillet over medium-high heat. Working in batches, add chiles, and cook, turning once, until toasted, about 2 minutes. Transfer all chiles to a large bowl; pour over 4 cups boiling water, and let sit until chiles are soft, about 30 minutes. Drain, reserving 1 1⁄4 cups soaking liquid, and remove stems and seeds from chiles. Transfer chiles and reserved soaking liquid to a blender along with garlic and onion; purée until very smooth, at least 2 minutes. Pour sauce into a bowl; set aside.
Bring a 4-qt. saucepan of salted water to a boil over high heat; add potatoes, and cook until just tender, about 10 minutes. Drain and set aside. Heat 2 tbsp. oil in a 12″ skillet over medium heat; add chorizo, and cook, stirring to break up into small pieces, until browned and cooked through, about 8 minutes. Add potatoes, and cook until potatoes are very tender, about 2 minutes; season with salt and pepper and set aside.
Using your fingers, scoop out and discard the insides of rolls, leaving a 1⁄2“-thick shell. Place about 1 cup potato-chorizo mixture on roll bottoms, and cover with tops; press sandwiches lightly to flatten and compact filling. Heat 2 tbsp. oil in a 12” skillet over medium-high heat. Submerge two sandwiches in chile sauce until thoroughly soaked, at least 10 seconds; place in skillet, and cook, pressing constantly with a metal spatula to flatten and flipping once, until browned on both sides, about 5 minutes. Transfer to a cutting board; repeat with remaining oil, sandwiches, and sauce. Open sandwiches and divide lettuce, cheese, and crema among sandwiches; close sandwiches again and serve warm.