Preheat the oven to 350 degrees. Grease and flour (or spray with baking spray) a rectangular cake pan (I used a 9x13).
Beat the eggs all at one time with the sugar on high speed until it is nice and frothy. Beat in the vanilla.
Beat in the sifted flour on medium speed in small doses.
Pour the batter into the prepared pan. Bake the Pan di Spagna for 30 to 40 minutes, until it is well risen and feels firm when pressed gently with the palm of the hand. Use a skewer to make sure the center is no longer wet if you have doubts about it not being ready.
While the cake is baking, prepare the whipped cream.
Chill a medium sized metal bowl in the freezer. Remove bowl from the freezer and add the heavy whipping cream to the bowl. Using a hand mixer on high speed, whip the cream until soft peaks begin to form; gradually add in the 1/4 cup of confectioner’s sugar. Continue to beat the whipped cream until it is thick and velvety. (about 1-2 minutes). Don’t over beat or you will have butter. Keep in the refrigerator while the cake is baking.
Check the cake after the first 20 minutes of baking to make sure it isn't getting too brown. Every oven is different. If needed, lower the temperature to 325 for the rest of the baking time. Let the cake cool on a rack. When the cake is cooled, cut the cake in half and spread the freshly whipped cream onto one layer. Top with the next layer. Carefully cut into the individual pieces and with dust confectioner’s sugar on top.