1/4 c. butter, melted
1 c. graham cracker crumbs
1/4 c. sugar
3 egg yolks
1 (14 oz.) can sweetened condensed milk
1/2 c. ReaLemon lemon juice
Few drops yellow food coloring, optional
Whipped topping

Combine butter, crumbs and sugar; press into 8 or 9 inch square pan. In bowl, beat egg yolks; stir in condensed milk and ReaLemon juice. Add food coloring if desired. Pour into crust. Top with whipped topping. Freeze until firm.