How to Make It
Roast the poblanos directly over a gas flame, in a dry skillet or under the broiler, turning often, until charred all over. Transfer the poblanos to a bowl and let cool for 5 minutes.
Rub the blackened skin off of the poblanos and make a slit in the side of each one, beginning 1/2 inch below the stem and ending 1/2 inch from the tip. Using scissors, carefully snip off the seed clusters at the base of the stems. Rinse off any stray seeds and bits of skin and pat dry. Lightly brush the poblanos with olive oil and season them inside and out with salt.
Preheat the oven to 375°. In a large skillet, heat the 2 tablespoons of olive oil. Add the yellow onion and garlic and cook over moderate heat until the onion is translucent, about 4 minutes. Add the ground beef and pork and cook, stirring, until no trace of pink remains; drain off the fat in the skillet. Stir the tomato sauce, currants, nuts and parsley into the meat mixture and season the filling with salt and pepper. Stuff the poblanos with the meat filling and arrange them snugly in a baking dish. Cover and bake for about 5 minutes, until they are heated through.
In a blender, combine the queso fresco, walnuts, sugar and milk and puree until smooth. Season the sauce with salt.
Transfer the poblanos to plates. Pour the walnut sauce on top, garnish with the pomegranate seeds and serve.