Process the sponge cake finely in a food processor. Melt the chocolate over a double boiler and mix it with the sponge cake crumbs.
It doesn't have to be blended completely - just mix it up roughly.
Add the heavy cream and combine. It should be moist and come together when you squeeze it. If it doesn't, add more heavy cream.
Roll into balls, one by one. When all the balls are finished, cover with plastic wrap and refrigerate for a while.
If you have almonds on hand, I recommend placing one almond in the center of each truffle.
Coat the truffles with tempered chocolate (or with chocolate that doesn't need tempering).
Optionally decorate with dragées or other toppings before the chocolate hardens completely.
When the chocolate coating has hardened, the truffles are ready. The outside will be crunchy and the inside will be moist. The texture is addicting!
Story Behind this Recipe
This is a recipe I've been making since I was in middle school To this day, people still often say to me, "Make those chocolate truffles again!" I make this often, whenever I have leftover sponge cake. The ingredient amounts don't have to be followed exactly! I always just eyeball the amounts.
This recipe is really easy, so I don't have any special hints for you. If you're not confident about tempering the chocolate, you can use the kind of chocolate that doesn't need tempering You can also substitute castella cake for the sponge cake! If you don't have a food processor, you can cut the sponge cake into small dice.