I highly suggest using the best chocolate you can find out there for this - ie Scharffenberger or Lindt. Anything else makes this recipe a fail from the moment you purchase a cheap chocolate.
Ingredients
Crust
21 chocolate sandwich cookies (such as Oreos)
1/4 cup (1/2 stick) unsalted butter, cut into pieces, room temperature
Mousse
12 ounces semisweet chocolate, finely chopped
1 teaspoon vanilla extract
Pinch of salt
3 3/4 cups chilled whipping cream
1/4 cup sugar
Chocolate shavings (optional)
Preparation
For Crust:
Preheat oven to 350°F. Butter 9-inch-diameter springform pan with 2 3/4-inch-high sides. Finely grind cookies in processor. Add butter and process until mixture is evenly moistened. Press crumb mixture onto bottom and up sides of prepared pan to form thin crust. Bake crust 5 minutes. Transfer crust to rack and cool completely.
For Mousse:
Bring 1 cup cream to boil in a medium sized heavy saucepan and whisk briskly, adding in the chocolate, vanilla and salt.Transfer mixture to large bowl. Cool to room temperature, stirring occasionally.
Beat 2 cups cream and sugar in large bowl to stiff peaks. Fold into chocolate mixture. Pour mousse into prepared crust. Chill until set, about 6 hours. (Can be prepared 1 day ahead.)
Beat remaining 3/4 cup cream in medium bowl to firm peaks. Transfer to pastry bag fitted with medium star tip. Pipe rosettes of cream around edge of cake. Garnish with chocolate shavings.
Serves 8.
