Some tips:

1) To make this sponge cake, we can use an electric mixer or a stand mixer; it’s important that the bowl is large because the volume of whipped eggs and sugar will quadruple.

2) The pan (24 cm diameter springform) should be greased and floured before starting to prepare the cake, to have it ready; the sponge cake batter should be poured immediately into the pan and baked just as quickly to ensure the air incorporated into the batter does not escape.

3) Sift together all three powders: rice, chestnut, and potato starch. When we add this mix to the egg and sugar mixture, we will sift it again to aerate it as much as possible and allow it to mix as quickly and evenly as possible.

4) The eggs should be used at room temperature. Take them out of the fridge about half an hour before.

5) Preheat the oven to 340°F (static) right before starting to prepare the sponge cake. It is essential that the oven has reached the temperature when we bake the sponge cake.

6) The final decoration of the cake made by me is just a suggestion. You can decorate it as you prefer. In my case, since I had three beautiful boiled whole chestnuts left over from the filling, I decided to glaze them with chocolate (melted in a bain-marie with two tablespoons of milk) to put on the cake. This step, optional, can be done a few hours before decorating the cake, so the chocolate has time to dry.

7) The sponge cake should rest for 6 to 12 hours after being baked. I recommend letting it rest for about 6 hours even after being soaked and filled because it will be much, much better. Obviously, this is just advice; adjust according to your needs.

Let’s prepare the sponge cake

Break the eggs into the bowl we have chosen, immediately add the sugar, salt, and spices, and whip continuously for 20 minutes (speed 4 if using a stand mixer whisk).

As the mixture whips, it will change color, going from yellow (from the eggs) to almost “cream white” (as in the photo below).

The success of a good sponge cake lies precisely in the air incorporated by the whipped egg and sugar mixture, which will allow us not to use any leavening agents and will give structure and softness to the final product.

After 20 minutes, turn off the mixer and add the flour mix in this way:

-pour a heaping tablespoon at a time, passing it through a sieve.

-then, gently immerse the whisk (by hand) into the whipped mass and incorporate the mix with a gentle motion that goes from the bottom (i.e., from the bottom of the bowl) upwards, ideally drawing almost a spiral, repeating this motion two or three times at most gently, before adding another tablespoon.

-continue like this until the mix is finished.

Pour immediately the mixture into the pan, gently level with the back of a spoon, and bake immediately on the middle rack. Do not open the oven during the baking of the sponge cake.

During baking, the sponge cake will reach the top edge of the pan and then gradually adjust, lowering in height and detaching from the sides of the mold.

At the end of baking, open the oven, do the toothpick test (which should come out dry), and turn it off. Leave the oven door open ajar for about ten minutes before taking the cake out of the oven.

The sponge cake should be left to cool for about half an hour and then removed from the mold and placed on a wire rack to cool. It should be left to rest for 6 to 12 hours before it can be cut, soaked, and filled.

Let’s prepare the soak

Pour the sugar, lemon zest (grated or peeled but without the white inner part, please) and the water into a saucepan.

Put it on the heat and bring to a boil. Let the mixture boil for 5 minutes, then turn it off and let it cool completely (I prepare it the night before or, in any case, a day in advance). The liquor should be added to the cold soak just before soaking the cake.

Let’s prepare the chestnuts.

In a pot, put the whole chestnuts, pour water to cover them, add a bay leaf, if desired, cover, and bring to a boil over high heat.

When the water comes to a boil, immediately lower the heat and let the chestnuts simmer for 20 minutes (for large chestnuts like marrons); 12/15 at most for small chestnuts. In my case, it took 20 minutes because they were large, as can be seen from the photo.

After 20 minutes, turn off and let them sit another 10 minutes in water. Then, drain them, let them cool for 5 minutes, and put them in a bit of room temperature water while peeling them, without burning ourselves (peel them immediately, to avoid problems later). Boiled chestnuts can also be prepared well in advance.

After the “rest” period of the sponge cake, we can proceed to cut, soak, and fill (also decorate if desired, which can be done immediately or shortly before serving, depending on the time available).

Wash and dry the grapes. Cut the berries into 4 parts and remove the seeds.

Let’s prepare the cream

Whip the fresh cream. As soon as the whisks start to leave noticeable marks, add the powdered sugar, vanilla paste, and drained spreadable cheese from any whey. Continue whipping for another minute, until the cream appears fluffy. For personal taste, the cream is not too sweet, to counter the sweetness of the fruit in the filling and the soak. Taste to see if it is to your liking.

Transfer the sponge cake already on the serving plate. Cut it in half, into two discs, with a long, sharp knife or a cake wire slicer (very convenient, at least for me).

Soak the first disc (the one on the plate) abundantly with the soak (the quantity I provided is more than sufficient, as I always prefer to prepare a little extra, but not all of it should be used).

With the help of a spatula, a spoon, or a piping bag, fill the cake. Add the crumbled chestnuts and most of the grape berries.

To spread the cream, I preferred to use the piping bag (already with the nozzle inserted because then I had to decorate the surface) to give a uniform height to the cream.

Place the second disc on the filled one, aligning the edges. Soak it generously as well.

The soak should be abundant but not excessive in sponge cakes because, generally, the cake is served the next day, and resting in the fridge tends to dry it out.

Between the two sponge cake discs, embed the remaining berries (cut) on the outer edge of the filling. (as in the photo below).

Place the remaining cream in a piping bag with a closed star nozzle and decorate, forming roses on the top of the cake. Add more whole grape berries and the chestnuts set aside and covered with chocolate (optional step, as described in point 6 of the tips).

The sponge cake stuffed with chestnuts and grapes is ready. Now all that’s left is to eat it.

The cake should be stored in a cake container in a cool place if the temperature permits; otherwise, it should be refrigerated.

Bon appetit