Pulse 36 wafer cookies in food processor until finely ground. Place crumbs in large bowl and stir in melted butter, 1 teaspoon sugar, and 2 teaspoons water until thoroughly moistened. Firmly press into the bottom and sides of a 9-inch pie plate. Pulse remaining 8 cookies until finely ground and set aside.

Place chocolate in large heatproof bowl and melt over a pan of barely simmering water, stirring, until smooth. Remove from heat.

Add 1 tablespoon water to small microwave safe bowl and sprinkle gelatin over the top. Let sit 5 minutes to soften. Heat in microwave on high power until just melted, 10 to 20 seconds.

Whisk 6 tablespoons coffee liquor into melted chocolate. Whisk in melted gelatin.

Whip 2 1/3 cups cream with 1 tablespoon sugar to medium peaks. Fold cream into chocolate in 3 batches, until just combined. Gently fold in reserved chocolate wafer crumbs. Pour into pie shell and chill until set, about 3 hours.

Whip remaining cup cream with remaining 2 teaspoons sugar to soft peak. Fold in remaining tablespoon coffee liquor. Serve on the side.