Broil chile peppers on an aluminum foil-lined baking sheet 5 inches from heat about 5 minutes on each side or until peppers look blistered.
Place chile peppers in a heavy-duty zip-top plastic bag; seal and let stand 10 minutes to loosen skins. Peel peppers. Gently split chile peppers open lengthwise, keeping stems intact; remove and discard seeds. Set aside.
Cook pork in hot oil in a large skillet over medium-high heat until it crumbles and is no longer pink. Add chopped onion and next 4 ingredients; cook, stirring often, 7 minutes or until onion is tender.
Stir in tomato and next 4 ingredients. Cover, reduce heat, and simmer 5 minutes. Stir in 1 teaspoon salt.
Stir together tomato sauce and next 3 ingredients in a small saucepan over low heat 5 minutes.
Spoon about 1/2 cup pork mixture into each pepper, and place in a lightly greased 13- x 9-inch baking dish. Pour tomato sauce mixture over peppers.
Bake, covered, at 350° for 30 minutes. Top with Walnut Cream Sauce. Garnish, if desired, and serve over Cinnamon Rice Pilaf.
Note: Small green bell peppers may be substituted for poblanos chile peppers. (Do not roast.) Proceed as directed. Bake 45 minutes or until peppers are tender.