Frozen Chocolate-Chip Meringata

Preheat the oven to 225° and position racks in the lower and middle thirds. Trace an 11-inch circle on the undersides of each of 2 sheets of parchment paper. Turn the paper over onto 2 large baking sheets.

在装有搅拌器的站立电动搅拌机的碗中，用中等速度的牙垢奶油搅拌蛋清，直到泡沫。将速度提高到高，然后跳动直至形成软峰。一次加入颗粒糖1汤匙，在增加之间跳动5秒。加入香草，打直到白色僵硬而有光泽，大约4分钟。

Transfer half of the meringue to a pastry bag fitted with a 1/2-inch plain round tip and pipe a ring of meringue just inside each drawn circle. Spoon the remaining meringue into the circles and spread it 1/2 inch thick. Bake the meringues for about 1 1/2 hours, until very pale but dry. Turn off the oven, prop the door open slightly and let the meringues cool in the oven for at least 6 hours, until dry and crisp.

In a bowl, using an electric mixer, beat 2 cups of the cream with the confectioners' sugar until firm. Fold in one-fourth of the chocolate. Spread the cream over 1 round, spreading it to the edge. Top with the second round, pressing it lightly. Freeze until the cream is firm, about 4 hours.

Meanwhile, melt the remaining chocolate in a bowl set over a pan of simmering water. Off the heat, whisk in the remaining 1/4 cup of cream and the espresso.

用锯齿刀,切the frozen cake into wedges and transfer to plates. Let stand for 10 minutes. Spoon some of the sauce on each wedge and serve.