As a general rule, Passover desserts are either the kind that do not need flour to begin with, or are the type that have been converted for Passover use by swapping out the usual flour for potato starch and matzoh cake meal. The chocolate cake here represents a third sort: a baked good that is supposed to be made with potato starch.
This is Julia Child’s Le Glorieux, from Mastering the Art of French Cooking, Volume Two. It is a genoise type of cake that is made with potato starch. A large amount of melted butter and chocolate is added to make this a light, but rich cake.I cut the recipe in half, making only one 8″ cake. The whole recipe calls for five eggs. I actually measured out 2 1/2 eggs, but, in retrospect, 3 eggs would have been fine. Instead of using the combination of semisweet and unsweetened chocolate (for half a recipe, you would need an ounce unsweetened and 3 1/2 ounces semisweet), I used all bittersweet (Schmerling Kosher for Passover 70 % bittersweet). Instead of butter, I went with margarine to make the recipe dairy-free (pareve). I had a Kosher for Passover orange almond liqueur, so I used that.
Observations: The cake is delicious, with a tender, rich crumb. It is not as chocolate-ey as Chocolate Nemesis, which sill holds its place as my favorite flourless chocolate cake. I actually think this cake would be better with much less margarine and a bit more chocolate (or maybe some cocoa powder). The orange undertone is lovely. With the suggested chocolate frosting (melted chocolate, orange liqueur, and butter or margarine) the chocolate and orange flavor would be intensified.
Despite being a Julia Child recipe, this is actually a rather easy and quick recipe.