Combine crumbs, 2 tbsps sugar and melted margarine. Remove 2 to 4 tbsps for the topping. Press the rest in the bottom of an ice cube tray or an 8 inch pie pan.
Beat egg yolks until thick and lemon coloured, combine with milk. Add lemon juice and peel; stir until thickened.
Beat egg whites until stiff but not dry. Gradually beat in the 3 tbsps of sugar. Fold gently into the lemon mixture. Pour into crumb-lined pan; sprinkle with the crumbs. Freeze until firm.
