Make a vertical slit down the side of each chile and carefully remove the seeds, leaving the stem intact.
Mix the veal and pork in a bowl. Add the salt and pepper.
In a large heavy skillet, over a medium heat, cook the oil with the onion until translucent. Add the ground meat and cook, breaking up any clumps, about 5 to 7 minutes. Add the almonds, pine nuts, cactus, raisins, and epazote. Cook and stir constantly, until the meat is done.
Remove the meat mixture from the heat and let cool.
Stuff the chiles with the meat mixture and put them on an ovenproof platter, covered with loosely tented foil. Place the platter in a warm oven while finishing the sauce.
Place the walnuts in a blender. With the motor running, add the milk slowly, until smooth and thick. Add the cream and blend well.
Cover the chiles with the walnut sauce and garnish with the pomegranate seeds and parsley.
Recipe copyright Mary Sue Milliken and Susan Feniger, 1997, all rights reserved