Combine gelatin and 1 cup sugar in a large micro proof mixing bowl and blend well. Stir in milk. Cook, uncovered, on Hi for 5 minutes, or until hot. Beat egg yolks in a small dish. Gradually stir in a small amount of hot milk mixture. Add to large bowl of hot milk mixture. Blend well. Cook, uncovered, on bake for about 4 minutes, or just until bubbles form around edge of bowl. Do not overcook or mixture will curdle. Stir in vanilla. Place bowl in a pan or bowl of ice water. Cool until custard mounds when dropped from a spoon. Beat egg whites until stiff but not dry. Fold into custard mixture. Fold in whipped cream. Turn mixture into a 2 quart mold. Chill in refrigerator until set. TO MAKE SAUCE: Clean and hull berries. Reserve 1 cup of the best berries for garnish. Force the remainder through a food mill, or blend in an electric blender container. Put through a strainer to remove seeds. Combine 1/2 cup sugar with cornstarch in a 1 quart micro proof mixing bowl. Gradually stir in 1 cup water. Cook, uncovered, on HI for 3 to 4 minutes, or until mixture comes to a boil and is clear. Stir once during cooking. Stir in lemon juice, butter and strawberry puree. Chill sauce. Unmold mousse on a serving platter. Garnish with whole strawberries. Serve with chilled strawberry sauce. Yield: 8 to 10 servings