For the Crust: In a food processor, pulse 36 wafer cookies until finely ground. Place crumbs in a large bowl and toss with melted butter, 1 teaspoon sugar, ¼ teaspoon salt, and 2 teaspoons water to evenly coat. Scrape crumbs into the bottom of a 9-inch pie plate and, using flat-bottomed drinking glass or measuring cup, compress firmly until crumbs are in a compact, even layer across bottom and sides of pan.

For the Filling: Place chocolate in a large microwave-safe bowl and microwave on high, stirring every 30 seconds, until melted and smooth, about 2 minutes. (Alternatively, nest bowl over a saucepan of simmering water and melt chocolate, stirring occasionally, until melted and smooth, about 5 minutes.)

Add 1 tablespoon (15 ml) water to a small microwave-safe bowl and sprinkle gelatin over the top. Let sit until gelatin has softened and hydrated, about 5 minutes. Microwave on high power until just melted, 10 to 20 seconds; let cool slightly.

In a bowl of a stand mixer fitted with the whisk attachment or in a large bowl using an electric hand mixer, combine 2 ⅓ cups cream, 6 tablespoons coffee liquor, melted gelatin, 1 tablespoon sugar, and salt. Whisk on low speed until sugar is fully dissolved, about 30 seconds. Increase speed to medium-high, and continue whisking until medium peaks form, 2 to 3 minutes.

Add ⅓ of the whipped cream mixture to the chocolate and, using a flexible spatula, fold until thoroughly combined. Add remaining cream and gently fold until cream is fully incorporated and no streaks remain. (Mixture may deflate slightly; that is okay.) Scrape into pie shell and chill until set, about 3 hours.

To Serve: In a bowl of a stand mixer fitted with the whisk attachment or in a large bowl using an electric hand mixer, whisk remaining 1 cup cream, remaining 1 tablespoon coffee liquor, and remaining 1 tablespoon sugar on low speed until sugar has dissolved, about 1 minute. Increase speed to medium-high and continue whisking until soft peaks form, about 1 minute. Serve with pie.