Put butter in 9 inch glass pie plate. Cook on HI for 45 to 60 seconds, or until melted. Add crumbs and sugar; mix. Press mixture into sides and bottom of pie plate. Cook on Hi for 1 1/2 to 2 minutes, or until heated. Rotate dish once during cooking time. Put pumpkin, brown sugar, cinnamon, nutmeg, ginger, and salt into a large micro proof bowl. Combine and cook on Hi for 1 1/2 to 2 minutes, or until mixture begins to boil. Cool 10 minutes. Remove cover from frozen whipped topping and cook on defrost for 1 minute, or until it begins to thaw. Stir carefully. Fold thawed topping and yogurt into cooled pumpkin mixture. Spoon into crust. Refrigerate about 4 hours, or until set Yield: 6 servings