How to prepare and apply syrup for cakes
The sponge cake should rest overnight, because that way it cuts better and absorbs the syrup properly.
The cake is better the next day. It needs to rest overnight to dry completely, making it easier to cut and allowing it to absorb the syrup better.
To cut the cake into slices, you'll need a large, long-bladed, serrated knife, although you can also use a thread. Remove the dark top layer with a thin sheet of parchment paper, and all the slices should be cut into equal portions.
When to moisten a sponge cake depends on its texture. A light, fluffy sponge cake doesn't need syrup because it absorbs enough moisture from the cream and softens on its own. A denser sponge cake or one with thicker layers, on the other hand, needs syrup to stay moist. If it has been left to dry completely and will be used within one to three days, it also needs to be soaked.
The syrup uses equal parts water and sugar. Boil the water and sugar together, then add alcohol such as rum or liqueur. For extra flavor, you can use honey, vanilla, or other flavorings. Coffee cream liqueur, or any creamy liqueur in general, is an excellent choice. Boil it for exactly 3 minutes and then let it cool completely.
The amount depends on the freshness of the sponge cake: fresh sponges absorb little, while drier sponges absorb much more. Apply the syrup with a brush, gradually moistening the entire surface, as too much can run onto the cream and prevent the sponge from setting properly. It's best to let it rest for a while to absorb the syrup, which should always be cold, since hot syrup can stain the sponge and alter its consistency.
