Mole Verde, or just "Verde" for short, is the lightest and freshest-tasting of Oaxaca's "seven moles." Fresh herbs (rather than spice accents) are what distinguish mole verde -- a puree of green herbs has to be added at the last minute.
In an electric coffee grinder or spice mill, or in a mortar, grind the whole cloves and cumin together. In a blender combine the ground spices with the chiles, tomatillos, onion, garlic, thyme, marjoram, and 1/2 cup of the stock. Blend on high until smooth, about 2 minutes. 2. Put the remaining stock in a large saucepan and bring to a boil; adjust the heat to maintain a gentle simmer. Add the puréed mixture to the hot stock and cook for 3 minutes.
Thin the masa by mixing it with 1 cup water. Whisk the thinned masa into the sauce and bring to a simmer, whisking constantly. Cook uncovered over low heat for 10 minutes, whisking occasionally. If lumps form, strain the sauce through a medium-mesh sieve, pushing with a spoon to force the lumpy bits through. The sauce should thicken to the consistency of whipping cream; if necessary, raise the heat slightly to reduce and thicken it.
Put the parsley, epazote and hoja santa in a blender or food processor; if using a blender, add a few tablespoons of water to facilitate blending. Process until smooth. Add the puree to the sauce and bring back to a simmer. Cook for 4 to 5 minutes. Serve immediately.