I have completed my experiment with creating a tiramisu bonbon. First I baked eggless "ladyfingers." I use quotes because although these looked similar to ladyfingers, they certainly did not have the light, airy texture or the taste. When baked for the time specified by the recipe, they tasted mostly of raw flour. Only after being baked for a half-hour or more until they browned a bit did they have any taste at all. I ended up throwing the leftover ones in the trash.
The mascarpone coffee ganache went well. I used instant espresso powder to obtain the coffee flavor, and it was successful. When the ganache was complete, I divided it into halves. Into one half I added pulverized ladyfingers, and with the other, topped the ganache with little cookies I had baked from the same batter.
The result: In the first batch, the crushed ladyfingers basically dissolved into the ganache with no discernible taste and not much texture. The second was more successful: after one day, the ladyfinger cookies maintained their texture; by the second day, they had some crispness but were noticeably softer. I feel sure the softening will continue (inevitable movement of moisture from wet item to dry). At least there was some pleasing contrast between the coffee ganache and the cookie (see below for alternative bonbon idea). The mascarpone was, however, the biggest disappointment. I think any taste it contributed was in my imagination. It is simply too mild a cheese to be tasted in proximity to the dark chocolate shell. In my version of Susanna Yoon's cheesecake ganache, I use cream cheese and sour cream, and although they also are mild, still they have some tang contrasted with mascarpone.
My conclusion is that I will probably not be adding tiramisu bonbons to my repertory of chocolates. If I made actual ladyfingers, they would dissolve in mush if added in pulverized form and probably do the same if added in cookie form because they are so porous (which is why they soak up the coffee in an actual tiramisu). As I ate this filling, I kept thinking that I would rather have had a bonbon with a layer of coffee ganache, topped with a small layer of hazelnut praline gianduja enclosing a shortbread cookie.
