2 tbsp. butter
2 c. crushed vanilla wafers
3 egg yolks
1/2 c. sugar
3 tbsp. lemon juice
1 c. heavy cream, whipped
3 egg whites, beaten

Butter well a 10-inch square pan. Line pan with wafer crumbs. Reserve 1/4 cup of crumbs for topping. Beat egg yolks with sugar and lemon juice. Add to whipped cream, then fold into beaten egg whites. Pour into pan and sprinkle with remaining crumbs. Place in freezer at least overnight. Cut in squares to serve.