As soon as I saw this post, I knew that I wanted to make this dessert. But, the recipe uses raw eggs that are not cooked all the way through (not recommended for kids). Then I remembered an episode of America's Test Kitchen where they made a triple chocolate mousse cake, with no raw eggs! So I used that recipe instead, and made them into individual cakes. The perfect occasion arose when we went to visit the California Academy of Sciences Museum with my friends Sue and Cecila and our significant others and kids - I made these as snacks for us, but we ended up eating them after the museum, following a belated birthday dinner for Sue.
Since I didn't have a whole bunch ramekins of the same size, I used four 3.5-inch ramekins, two 3-inch ramekins, and then improvised with four additional 3-inch cake rings with which I lined the bottom with aluminum foil. I buttered all of these and then dusted them with cocoa powder.
The bottom layer of the dessert was a moist chocolate cake. The recipe from ATK uses a flourless chocolate cake, but I decided to use my favorite homemade chocolate chocolate recipe instead. This may have been a bad decision, as the cake baked in the cake rings all fell apart when I unmolded them! I suppose the flourless chocolate cake would have provided a more stable and dense cake, but in the end I was glad I went with the regular chocolate cake, since the resulting cake was very moist and not too heavy with the mousse.
After trimming the cakes to be one-inch tall and then surrounding them with little parchment paper cuffs, I used a pastry bag to pipe and fill them with the middle layer - a rich bittersweet chocolate mousse - and then let them set in the fridge for about an hour. Then I piped the top layer, which was a light white-chocolate mousse. Normally I am not a big fan of white chocolate, but in this case it complimented the dessert well (and made for a nice color contrast).
And with the leftover pieces of cake trimmings and leftover mousse, I used drinking glasses to assemble little parfaits (can't let leftover cake and mousse go to waste!).