1/2medium white onion, coarsely chopped (about 1/2 cup)
3medium clovesgarlic
1tablespoondried oregano
1/2teaspoonground cinnamon
1/2teaspoonground allspice
1/2teaspoonfreshly ground black pepper
5whole cloves, stems removed
2 1/2teaspoonskosher or coarse sea salt
3tablespoonssafflower or vegetable oil
4poundsbeef round roast or brisket, cut into 4-inch chunks
1poundBanana leaves, or aluminum foil
12ounceslight beer, 1 bottle
24small slider buns, brioche or challah buns are specially good with this!
Pickled jalapeños, optional
To Prepare
For the marinade:
Heat a large skillet or comal over medium heat. Add the dried guajillo and ancho chiles and toast them for no more than 20 seconds per side, taking care not to burn them. Transfer the toasted chiles to a medium saucepan and add the water, place over medium heat and cook for 12 to 15 minutes, until the chiles have softened and rehydrated.
Transfer the chiles to a blender, and add 2 cups of their cooking liquid (discard the remaining liquid), the vinegar, tomato, onion, garlic, oregano, cinnamon, allspice, black pepper, cloves and salt. Puree until smooth.
Wipe out the medium saucepan and add the oil. Place over medium heat for 1 to 2 minutes, then add the pureed chile mixture, being careful to avoid any splatters. Partially cover and cook for 10 to 12 minutes, stirring once or twice, until the color darkens and the mixture thickens to a paste-like consistency.
For the meat:
Place the beef in a large bowl and cover it with the marinade. If you will not cook it that day, cover and place in the refrigerator for up to 48 hours. Wrap the individual meat chunks in pieces of banana leaf or aluminum foil as you would wrap burritos or tamales - making sure to add a generous amount of marinade in each packet.
Preheat the oven to 350°F. Place the meat packets inside a large, heavy ovenproof French oven or casserole, pour in the beer and cover with a tight-fitting lid. Roast for about 3 hours, until the meat is succulent and comes apart when pulled with a fork. Transfer to the stovetop (off of the heat), and let everything rest for 10 to 15 minutes before opening the meat packets.
Serve on slider buns with drunken salsa and/or pickled jalapeños.