30 chocolate wafer cookies
3/4 cup sugar
1/4 tsp salt
6 Tbs melted butter
2 Tbs plus 1/4 cup sugar
114g dark or bittersweet chocolate, chopped
1 Tbs cocoa powder
4 egg yolks
1 cup heavy whipping cream
3/4 cup mascarpone cheese
Chocolate shavings and freshly whipped cream to garnish
For the crust, heat oven to 350 F. Pulse the cookies, sugar and salt in a food processor until fine crumbs form.
Add the butter and pulse until the mixture is moistened and holds together when you pinch it. Press about 2 tablespoons of crumbs onto the bottom of each of four 4 x 1 3/4-inch mini spring form pans (or use one 8-inch spring form pan). Place the pans on a baking sheet and bake 5 minutes.
Put 2 tablespoons of the sugar and 1/4 cup water in a small saucepan over medium heat until the water simmers and sugar is dissolved; add the chocolate and cocoa off the heat and stir until completely smooth.
Transfer to a large bowl and cool for 10 minutes.
Beat the egg yolks and remaining 1/4 cup sugar with an electric mixer and the whisk attachment on medium-high speed until light in color and thickened enough to form a ribbon, or about 5 minutes. Fold the egg yolk mixture into the cooled chocolate until evenly blended.
Wash the mixer bowl and add the cream and mascarpone, beating on high speed until soft peaks form.
Gently fold the cream into the chocolate mixture.
Divide the mixture among the 4 pans (or, if using one 8-inch pan, scrape it all in).
Cover pans with plastic wrap and freeze for at least 6 hours or overnight.
Remove semifreddo from the freezer 15-30 minutes before serving, depending on how firm it is. Unmould and serve with some whipped cream and chocolate shavings over the top to your liking.
4 x 1 3/4 inch mini spring form pans or one 8 inch spring form pan.