1. In a food processor fitted with a metal blade, pulse chocolate sandwich cookies until finely ground. (You should have about 3 cups/750 mL.) Add melted butter and process just until combined. Firmly press cookie mixture onto bottom and up side of prepared pan. Freeze for 20 minutes to firm up crust.

2. Filling: Meanwhile, in a large microwave-safe bowl, combine chocolate chips and 1 cup (250 mL) of the cream. Microwave on High for 2 ½ minutes, stirring every 30 seconds, until chocolate is shiny and almost melted. Stir until smooth. In clean food processor bowl, process chocolate mixture and Kirsch until smooth.

3. In a large bowl, whip remaining cream until stiff peaks form. Add cooled chocolate mixture and whip until incorporated. Spread filling over prepared crust and refrigerate until firm, about 6 hours, or overnight.

4. Topping: Whip cream with confectioner’s sugar and vanilla until stiff peaks form. Spread over chocolate mousse layer and refrigerate for 1 hour or until firm, or freeze for 20 minutes. Carefully run a knife around edge of pan before removing side. Do not remove bottom of pan. Slice and serve cake directly from bottom of pan.

Variation:

Substitute another liqueur for the kirsch (cherry brandy), such as Irish cream, crème de cacao or crème de menthe.