Preheat the oven to 450 degrees F.
Place four 9-inch oval au gratin dishes (or one large oval
glass lasagna pan) on a baking sheet. In each small dish place
1 teaspoon of butter and 1 teaspoon of jelly. (If you are
using a lasagna pan, smear the bottom with the butter and
then with the jelly.
Combine the egg whites, vanilla sugar, and lemon zest in a
large metal bowl. Beat with an electric mixer at high speed
until stiff peaks form.
Beat the egg yolks with the granulated sugar. Gently fold
the egg yolks and flour into the meringue. Use a spatula to
place three large mounds of the mixture into each au gratin
dish. Smooth the surface of each and bake for 8 minutes, until
puffed and golden.
Serve immediately. This is especially good with Vanilla Sauce,
warm Chocolate Sauce, or cold Strawberry Sauce (recipes separately).