Fundamental Joconde Technique

Hi, António. Joconde is an excellent sponge to use for rolled cake. If it cracks when you roll it, it can mean that the sponge was over-baked.

We are often told that a cake is done when it pulls away from the sides of the pan, but this is incorrect. You'll want to bake it just until it springs back when touched lightly. You'll notice that for something like the joconde Chef Russ makes here (quite thin and baked at a high temp), it is not in the oven for very long at all.

There are also some differences of opinion on the technique for rolled cakes. Some like to dust the sponge with powdered sugar and roll it in parchment or a clean towel while it is still quite hot, then let it cool, unroll it, fill it, and then roll it back up. This pre-shapes it, plus wrapping the warm sponge like that also locks in some moisture. However, many chefs prefer to allow the cake to cool in the pan and then fill it. I would recommend you try both methods - you may find one way works better for you than the other.