Tom Roach’s Attractive Angel Meals Plum-cake

Factors:

• 1½ cups sifted plum-cake flour
• 1½ cups superfine sugar
• 1½ cups egg whites (from 11–12 mountainous eggs)
• 1½ tsp. cream of tartar
• 1 tsp. vanilla extract
• ½ tsp. heavenly sea salt