Set a 12" cast-iron skillet over medium heat for five minutes. Add the allspice berries, black peppercorns, oregano, and cloves; toast, shaking the pan, until fragrant, about 15 seconds. Remove from the heat, transfer to a spice grinder, and grind to a fine powder.

Reheat over medium heat. Add the garlic cloves and toast, turning them from time to time, until softened slightly and blackened in spots, about six minutes. Turn off the heat, remove the garlic from the skillet, and set aside to cool at room temperature. Once they are cool enough to handle, peel the garlic cloves and discard the skins.

Heat a gas grill with the burners turned to high. Place the arbol chiles on a grill pan, and grill, using tongs to turn and stir the peppers, until they are uniformly black and brittle, but not to ashes. Transfer the chiles to a bowl, then repeat with ancho chiles and put them in the same bowl. Cover the chiles with hot tap water, then put a heavy plate over the filled bowl to keep the chiles submerged. Set aside to soak for thirty minutes.

Drain the chiles and rinse under cold water until it runs clear. Return the chiles to the bowl and repeat the process of covering with hot tap water, using a plate to keep the chiles submerged, and soaking for thirty minutes.

Drain the chiles and transfer to a blender along with the ground spices, roasted garlic, vinegar, salt, and a half cup of water; pureé to a paste. Transfer to a container and refrigerate until ready to use. This will keep in the fridge for three months.

Watch out! The original recipe calls for broiling the peppers, but whew, this is as intense as I can handle it, outside on the grill.