For the chiles:
With a sharp knife, cut open the chiles from the side and carefully remove the seeds but leave the stem intact. In a saucepan, bring the water and piloncillo to a boil and stir to dissolve.
Reduce the heat to medium-low, add the chiles, cook for 3 minutes, cover and remove from the heat. Allow the chiles to soak for 15 minutes or until soft, then place the chiles on paper towels to dry and set aside.
For the picadillo:
In a large Dutch oven, heat the oil over medium heat. Add the onion and sauté for 3 minutes. Add the chicken and fry it until almost cooked—about 4 to 6 minutes.
Add the garlic and sauté briefly, then add the tomatoes and cook until they change color. Add the rest of the ingredients and season with salt and pepper, to taste. Cook for 10 minutes more, then remove from the heat and set aside.
For the salsa:
Place the onion, garlic and tomatoes in a blender and blend to make a smooth puree. Heat the oil in a medium saucepan, add the tomato mixture and fry until it changes color.
Add the bay leaves, cream and salt and pepper. Reduce the heat and keep the salsa warm until serving time.
To finish:
Heat the oven to 325°. Stuff each prepared chile with some of the picadillo and line the chiles in a baking dish sprayed with nonstick spray.
Cover with aluminum foil and bake until heated through—about 15 minutes. To plate, pool some of the salsa on each plate and place a stuffed chile on top.