Passover starts next week, and if you're looking for a dessert that goes beyond the classic macaroons and meringues, check out this icebox cake made with sheets of matzo and chocolate mousse. The recipe is from pastry chef Zac Young—owner (aka "Sprinkle Master") of the groundbreaking direct-to-consumer bakery PieCaken—who is known for his creative and tasty sweet treats, including these adorable gnome cupcakes.
In a small glass, stir together the wine and sugar until the sugar dissolves. Pour the wine mixture into an 8 x 8-inch baking dish and set aside.
In a microwave-safe bowl, add 1 ½ cups of the chocolate chips and 1 cup of the cream. Microwave in 30 second intervals, stirring vigorously in between, until the chocolate chips have just melted, about 1 ½ minutes total. Whisk until smooth, transfer to a large bowl and let cool until just slightly warm, about 10 minutes.
In the bowl of a stand mixer fitted with the whisk attachment, add the remaining 3 cups of cream and the powdered sugar and salt. Whisk on medium-high speed until the cream almost forms stiff peaks. Briskly fold half of the whipped cream into the chocolate mixture until mostly incorporated (a few white streaks are fine). Fold the remaining whipped cream into the mousse.
To assemble, pull a piece of plastic wrap over a plate or platter large enough to fit an entire sheet of matzo, leaving about 8 inches on either side of it. Soak 1 sheet in the wine, fully submerging it for about 30 seconds until it absorbs the wine, but isn't so soggy that it falls apart. Transfer it to the center of the plate, top with 1 cup of the chocolate mousse and spread the mousse into an even layer with a spatula or knife.
Soak another sheet of matzo and repeat the process until you have used all the mousse—about 6 layers total—and end with the mousse on top. Take the overhanging plastic wrap and pull it up and over the sides and top of the assembled cake, using it to help square off the sides. Refrigerate overnight, or for at least 4 hours.
To finish, make the chocolate glaze. Place the remaining ½ cup of chocolate chips in a microwave-safe bowl and microwave in 20 second intervals, stirring after each one until the chocolate has melted, about 40 to 60 seconds total. Add the oil and stir until smooth.
Unwrap the chilled cake and place it on a serving plate. Pour the chocolate glaze over the cake and refrigerate until ready to serve. To serve, dip a sharp knife in hot water and cut into slices.