Baking the Lemon Sponge:
Preheat oven to 350 degrees F, with rack in center of the oven. Line two 8-inch cake pans with parchment paper and grease the paper.
Beat the sugar, zest, and eggs in a stand mixer using the whip attachment, on high speed for about 5 minutes. The eggs will be light in color and very thick.
Sift the flour over the egg mixture and fold it in carefully with a rubber spatula.
Pour into the prepared pans and quickly spread it out evenly.
Bake for about 18-20 minutes or until a tester comes out clean.
To assemble the cake:
Cut each of the cakes in 2 layers. Place one layer of the cake on a 8-inch cardboard cake round. Spread 1/4 cup preserves on the cake, followed by 1/4 cup lemon curd. Repeat with the next two layers of cake, preserves and lemon curd. Finally, top with the last layer of cake.
To decorate the cake:
Use a large rose tip, to make the flowers and to pipe the striped base. Starting at the top edge of the cake with the narrow end of the rose tip facing up, pipe a continuous spiral all the way down the cake, being careful to overlap the previous stripe.
Use a propane blowtorch to lightly toast the meringue; which gives it a lovely marshmallow flavor. (Be very careful to do this on a fireproof surface.) The cake can also be served without toasting the meringue; the pure white icing is also gorgeous.
For information and a how-to video about piping the roses visit www.zoebakes.com.
To make the meringue:
Whisk together the egg whites, sugar and salt in the bowl of your stand mixer. Rest the bowl over a pot of simmering water to form a double boiler. Scrape down the sides of the bowl so that all the sugar is off the sides of the bowl. Continue to stir the mixture until all the sugar is melted into the eggs and you no longer feel any graininess when rubbed between your fingers, about 3-5 minutes.
Place the bowl onto your mixer, add the vanilla and salt, whisk on high speed until the meringue is thick and glossy and the bowl is just warmer than room temperature, about 8 minutes.
To make the Lemon Curd:
In a large bowl, whisk together the yolks and sugar. Whisk in the lemon juice, salt and zest. Place the bowl over a medium sized saucepot that has an inch of simmering water in it. Using a tempered rubber spatula stir the lemon mixture over the heat until it thickens. This can take 5 to 10 minutes. As the lemon curd thickens it should cling to the rubber spatula. It will be thick like a pudding.
Remove from the heat and stir in the butter. Strain the curd into a container and cover with plastic. Put in the freezer for about 15 minutes, or until the curd is cold but not frozen. Remove and place in refrigerator until ready to use. It will be good for up to 5 days in the refrigerator.
