Combine lime juice and sugar in saucepan; heat, stir- ring, until sugar is dissolved.
Bring to a boil.
Beat egg yolks lightly; stir small amount of hot mixture into egg yolks.
Return to hot mixture; reduce heat and cook, stirring constantly, until custard is thickened.
Whip egg whites until stiff peaks form; fold egg whites, nuts and whipped cream into cus- tard.
Spread half the cracker crumbs in greased 8- inch square pan; pour custard into pan.
Spread re- maining cracker crumbs over custard.
Refrigerate for at least 4 hours before serving.