Combine first seven ingredients.Whisk ingredients. Cook in microwave, 2 minutes at a time, stirring after each. Cook till thick about 8-10 min. depending on power of microwave. Chill till almost set, stir in pumpkin. Cool. While cooling, beat egg whites with 1/2 cup sugar until stiff & glossy. Fold into pumpkin mixture. Pour into pie crust. Chill 2-3 hrs.