Place wafer cookies in a food processor. Pulse until the crumbs are fine and uniform in size.
Combine cookie crumbs, sugar, and salt. Mix, then add melted butter. Coat the crumbs until the butter is even in distribution.
Spread the crumbs even across the bottom of the pie plate. With your hands, a tart tamper, or the back and side of a small measuring cup, press the cookie mixture firm into the bottom and up the sides of the pie plate. Refrigerate for 5-10 minutes.
On the center oven rack, bake the crust until firm, about 10 minutes. Remove and cool completely on a wire rack.
Coffee Cream Filling
Place a fine sieve over a large bowl alongside coffee liqueur, vanilla, and cut butter.
In a medium saucepan, whisk sugar, 2 Tablespoons espresso powder, cornstarch, and salt together. Whisk in milk and egg yolks. Run a spatula along the corners and bottom of the saucepan, making sure the mixture is well combined.
Place the saucepan over medium-high heat. Whisk nonstop until the mixture boils and thickens, about 7 minutes. Stir continuously for 60-90 seconds. Remove from heat and strain through a fine sieve. Stir in coffee liqueur and vanilla, then butter one piece at a time until melted. Let mixture cool for 10 minutes, stirring occasionally, then pour into the cooled pie plate and smooth with a spatula or spoon.
A few options for preventing a skin from forming:Press a piece of plastic over the surface of the pie, leaving as little gaps or air pockets. Glide a piece of butter across the surface of the pie or a light coat of vegetable spray, then press an unbleached piece of parchment paper over the pie (leaving as little gaps or air pockets).Place the pie on a wire rack to cool, then refrigerate for at least 4 hours or overnight.
Coffee Bean Whipped Cream
About 15 minutes before serving, chill a medium (preferably glass) bowl and mixer beaters in the freezer.
With the flat side of a chef's knife, crush espresso beans one at a time. Reserve 1 Tablespoon whole beans.
Using an electric mixer, start at medium low speed and work to high. Beat cream, confectioners' sugar, and espresso powder until stiff peaks form. Avoid over beating, as past stiff peaks the whipped cream will begin to deflate.
Fold half of the crushed espresso beans into whipped cream, then (using a large tip) pipe or spread whipped cream over the pie. Garnish with remaining crushed and whole dark chocolate beans.
The crust can be made the day before, cooled, and covered.
The holidays are busy, a store bought crust can be filled too.
Coffee Cream Filling
if making a cream pie for the first time: at about seven minutes, you'll feel the cream change or thicken. While still over the heat, stir quickly for 60-90 seconds. If the cream bubbles too much, either lift the pot slightly while continuing to stir or reduce the heat a little. This is the make or break moment for the success of a cream pie. If never reached, the pie won't hold its form.
Whipped Cream
for the best whipped cream, use a medium-sized deep glass bowl.
place the bowl and beaters in the freezer for a minimum of fifteen minutes.
for whipped cream that best holds form without stabilizing, look for heavy cream with at least 6 grams total fat or 20% saturated. Clover, Trader Joe's, and Straus Family Creamery contain the above amount of fat and make amazing whipped cream.
whipped cream can be made early, covered, and refrigerated for up to a few hours.