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

Combine butter, crumbs and sugar. Press into 8 or 9-inch square pan. In bowl, beat egg yolks, stir in sweetened condensed milk, then add lemon juice and food coloring, if desired. Pour on top of crust. Top with whipped cream. Freeze until firm.