This is a super easy, fun, delicious, and pretty dessert.
Lemon Jelly Roll
For the lemon Curd (this batch makes a lot: enough for 2 jelly rolls + 1 small jar of curd!)
finely grated zest of 2 medium lemons
fresh-squeezed juice of 4 medium lemons (about 1 cup)
1 1/3 cups sugar
4 large eggs
1 3/4 sticks (3/4 cup plus 2 tablespoons) unsalted butter, cut into tablespoon pieces
Whisk together the zest, juice, sugar, eggs, and a pinch of salt in a 2-quart heavy saucepan set over medium heat. Continue whisking so the eggs don't lump. When hot to the touch, add the butter all at once and cook over moderately low heat, whisking constantly, until curd is thick enough to hold the marks of the whisk and the first bubbles appear on the surface, about 10 minutes. Immediately pour curd through a fine sieve into a bowl, cover with plastic wrap and chill.
For the cake:
4 eggs, separated
finely grated zest of 1 medium lemon
juice of 1 medium lemon
3/4 cup sugar
1 tablespoon vanilla
3/4 cup cake flour, sifted
3/4 teaspoon baking powder
1/4 teaspoon salt
Powdered sugar, sifted
Preheat oven to 400 degrees F. Line a 15 x 10 x 1-inch jelly roll pan or baking sheet with parchment paper and butter the parchment well.
In a medium bowl beat the egg whites until stiff but not dry and set aside. In a large bowl, beat the egg yolks until light. Add the lemon juice and lemon zest. Gradually add the sugar and vanilla, and mix well. In a small bowl, sift together the flour, baking powder, and salt. Add the sifted flour mixture to the egg yolk mixture. Fold the egg whites into the egg and lemon mixture and pour the batter into the prepared pan. Bake 10-15 minutes or until the cake is golden.
While the cake is baking, prepare a surface for rolling: place a dry, clean tea towel on a countertop and dust it well with powdered sugar. Invert the cake onto the dusted towel using your hands and a wide, flat spatula. Don't fret about flipping the cake, it'll be quite flexible. Trim 1/4-inch edge off each long side and, beginning with the end closest to you, roll the cake and towel up together and set seam-side down. Let this sit and cool to room temperature, about 15–20 minutes.
Once the cake has cooled, gently unroll it and spread generously with the chilled lemon curd. Roll it up kind of loosely (sans towel of course), to keep as much of the curd in as possible. A lot will run out the sides and far end but most if it will stay inside. Lay the jelly roll seam-side down again, keeping it on the towel, and sprinkle with powdered sugar. Transfer to a clean sheet of parchment, gently wrap the roll up and chill it for at least an hour or overnight.