1. In a food processor or a Ziploc bag crush the cookies into fine crumbs. Add melted butter and pulse until combined. Press the mixture into the bottom and up the sides of an 9-inch (23cm) tart pan with a loose base. Refrigerate while preparing the filling.2. Chop dark chocolate and place in a large heatproof bowl. Add heavy cream, butter and place over a pot with simmering water (double boiler), and melt completely, stirring occasionally. Or melt in the microwave in a 30 second pulses.3. Pour chocolate mixture over the crust. Refrigerate for 2-3 hours or until set. Decorate with strawberries (optional).