Crust: Preheat oven to 350°F In processor, pulse ingredients to form fine crumbs. Press onto bottom of 9 inches springform pan.
Bake 8 minutes, until set. Cool on rack. Wrap pan with heavy-duty foil.
Filling: In glass measure, combine chocolate, 2 Tbsp rum and coffee powder; microwave on HIGH 30 seconds; stir until smooth. Stir in remaining rum; cool. In large bowl, beat cream cheese, sugar, flour and extract until smooth. Beat in eggs, 1 at a time, just until mixed. Remove 2 ½ cups cream-cheese mixture; cover.
Stir cooled chocolate-coffee mixture into remaining cream cheese mixture. Pour over crust. Set springform pan in center of large roasting pan; place on oven rack. Pour boiling water into roasting pan to reach halfway up springform pan. Bake 25 minutes, until sides are set (center will be soft). Remove pan from oven; pour reserved cream cheese mixture in a ring over outside edge of set chocolate mixture. Gently spread evenly over entire surface.
Bake 35 minutes, until center is almost set. Turn off oven; let stand in oven 30 minutes, with oven door closed. Remove from waterbath to rack. Cool. Cover; refrigerate 8 hours or overnight. Remove sides of pan. Garnish.