This classic French cake is composed of two layers of a meringue filled with an egg-yolk-based buttercream. Often, the layers are of a meringue "japonais," which means with ground nuts added; you can use blanched almonds or hazelnuts (my favorite). While this dacquoise is based on layers of meringue japonais, it is held together with a sour cream ganache: a blend of sour cream and milk and dark chocolates. I find the combination of hazelnut meringue and sour cream ganache to be spectacular! Please use the best chocolates you can find.

You will need two large baking sheets (about 17" by 12") for the meringue, as well as baking parchment with which to line the sheets. You'll also need a corrugated cardboard cake circle (or something similar) that is 10" in diameter, and an oven that can maintain a low temperature for a long period of time (check yours with a thermometer--some ovens have trouble with this). While the meringues cannot be made on a humid day, they can be made well ahead and stored airtight at room temperature. This is best served about 2 to 4 hours after completion, when the meringues will still have much of their crispness. Though it can be served for several days after it is made, the meringues will no longer be as crisp. Do not freeze dacquoises.