Wash and griddle-dry the chiles. Place in a small bowl; cover generously with boiling water and let soak for at least 20 minutes. Drain the soaked chiles and reserve.
While the chiles soak, prepare the vegetables. Using a griddle or cast-iron skillet thoroughly heated over low heat, roast the tomatillos, green tomato, onion, and garlic. Remove each to a bowl to catch the juices as it is done and set aside.
Grind the peppercorns and cloves together in an electric coffee or spice grinder or with a mortar and pestle. When the roasted onion, garlic, and tomato are cool enough to handle, peel them over the bowl to catch the juices. Place the vegetables in a blender with the drained chiles and ground spices. Process to a smooth purée (about 3 minutes on high). With a wooden spoon or pusher, force the purée through a medium-mesh sieve into a bowl.
In a medium-size saucepan, heat the lard over medium heat until rippling. Add the puréed sauce and cook, covered, for 10 minutes, stirring occasionally. Stir in the salt.
In a small bowl, mix the masa with ½ cup water and whisk into the sauce. Bring back to a simmer and cook, whisking constantly, until the sauce is somewhat thickened and the flavors well blended, about 15 minutes.
The amarillo is now ready to use as a filling, a thick sauce for tamales, or an accompaniment to what strikes your fancy. Mixed with shredded chicken and folded into tortillas, it is the filling for Empanadas de Amarillo. I love it as a vibrant complement to Tamales de Chepil, or as a filling for other tamales.