London Sponge

Directions

1. 1
   On waxed paper, sift together 3 times, 1/2 cup of the sugar and the cornstarch.
2. 2
   In a large bowl beat together the whites of the eggs, cream of tartar and water until soft peaks form.
3. 3
   Add egg yolks and vanilla.
4. 4
   Beat just until blended.
5. 5
   Fold in sugar/cornstarch mixture a little at a time, until no dry particles are visible.
6. 6
   Bake in 2 ungreased 8 x 1 1/4-inch round cake pans in a preheated 350° oven until top springs back when lightly touched (about 30 minutes).
7. 7
   Cool in pans on wire racks.
8. 8
   Loosen edges and ease out.
9. 9
   Fill with jam.
10. 10
    Sprinkle confectioners sugar on top.