Cook sweet potatoes in boiling water to cover 45 minutes or until tender. Drain, cool, and peel. Beat sweet potatoes, 1/2 cup butter, and cardamom at medium speed with an electric mixer until smooth. Set aside. Cook gold potatoes in boiling water to cover 10 minutes or until tender. Drain. Beat gold potatoes and remaining 1/4 cup butter at medium speed with electric mixer until mashed. Add sour cream and next 3 ingredients, beating until smooth. Add milk, 1 tablespoon at a time, beating until desired consistency. Drop alternating heaping tablespoons of potato mixtures into a lightly greased 13- x 9-inch baking dish. Swirl gently with a knife. Bake, covered, at 325? for 30 minutes or until thoroughly heated. Garnish, if desired. Makes 10 servings. Kathy Hunt, Dallas, Texas Notes: Potatoes may be covered and refrigerated for 24 hours or frozen up to 2 weeks. Thaw frozen potatoes in refrigerator; bake at 325? for 1 hour or until thoroughly heated. Recipe by: Kathy Hunt, Dallas, Texas Posted to MC-Recipe Digest V1 #1047 by Suzy Wert on Jan 27, 1998