Beat egg yolks 2 minutes, add sugar and salt; beat until mixture is thick and creamy. Scald milk and light cream. Pour liquid into egg yolks and stir vigorously. Place in pan and heat slowly until thickened. Cool and chill. Stir in vanilla. Fold in whipped cream and pour into ice cube trays and freeze until center is mushy (1-2 hours).
Place freezing mousse cubes in bowl and beat until smooth, fold in peaches and cover with plastic wrap and freeze (4-6 hours). Top with sauce.
Sauce: Put 4 cups peaches into a blender, 1 cup at a time and puree at low speed. Cube the remaining 2 cups peaches. Stir into puree with lemon juice and brandy. Cover and chill. Spoon over mousse.
