Preheat oven to 350.
Spray 2 (9") round cake pans with nonstick spray.
Line bottoms with parchment or wax paper and spray paper with nonstick spray.
TO MAKE CAKE:.
Combine flour, baking powder and salt in medium bowl.
Whisk milk, 3/4 cup sugar, egg substitue, and oil in large bowl, whisk in flour mixture just until blended.
With electric mixer on medium speed, beat egg whites in another large bowl until soft peaks from.
Add remaining 4 Tablespoons sugar, 1 tablespoons at a time, beating until firm peaks form.
With rubber spatula, gently fold beaten whites into flour mixture until no streaks of white remain.
Divide batter evenly among pans.
Bake until toothpick inserted into center of each layer comes out clean, 30-35 minutes.
Run knife around each layer to loosen from pan.
Invert each layer onto rack; remove parchment paper.
Let cool completely.
With long serrated knife, split each layer in half to make a total of 4 layers.
Arrange 3 layers cut side up on work surface; spread each with 2 tablespoons lemon curd.
Place 1 layer filling side up on serving plate.
Top with 2 more layers, filling side up.
Cover with reamining cake layer, cut side down.
If making ahead can wrap cake tightly in plastic wrap and then foil, and freeze up to 1 month.
Let thaw in refrigerator overnight.
TO MAKE FROSTING:.
Whisk egg whites and sugar in large metal bowl of electric stand mixer,.
Set bowl in large saucepan over 1 inch of simmering water.
Cook, stirring constantly, until sugar is dissolved and mixture is hot, 5-7 minutes.
Transfer bowl to mixer; add vanilla.
With whisk attachment on medium-high speed, beat until stiff glossy peaks form and mixture is completely cool, 5-7 minutes.
Spread frosting at once over tiop and sided of cake.
ADD a FLOURISH:.
Flame frosting to add pizzazz, ignite a hand held torch and move flame continously in small circles over frosting until it is lightly browned as in a meringue pie.