Prepare pie crusts according to package directions for one crust filled pie using two 9" pie pans. Flute edges to form a high rim. In small bowl, combine remaining crust ingredients; mix well. Spread half of mixture evenly over bottom of each crust; refrigerate. Heat oven to 425 degrees. In medium bowl, combine sweet potatoes and butter; mix well. Set aside.
In large bowl, combine eggs and 1 c sugar; beat well. Add sweet potato mixture and remaining filling ingredients except walnuts; mix well. Stir in walnuts.
Pour into crust-lined pans. Bake pies for 10 minutes. Reduce temperature to 350 degrees; bake an additional 45 to 55 minutes or until knife inserted near center comes out clean. Cool completely.
Just before serving, fold orange peel into whipped cream; spread over pies. Store in refrigerator.
Makes 2 pies of 8 servings each.