How to Make It
Pulse the cookies in the bowl of a food processor until mostly finely ground (you should have about 2 cups). Add the melted butter, 2 tablespoons sugar, and a pinch salt and pulse until just combined. Using a flat-bottomed measuring cup, press the mixture into the bottom and up the sides of a 9½-inch deep-dish pie plate. Place in the freezer and chill until firm, about 10 minutes.
Heat oven to 350°F. Bake crust until browned and the edges are crisp, 14 to 16 minutes; crust will firm up as it cools. (If the sides slouch in the oven, press back up while the crust is still warm). Let cool completely, about 30 minutes.
Remove the ice cream from the freezer and let sit until softened slightly, about 5 minutes. Scoop into a medium bowl and stir until softened and spreadable. Spread the ice cream evenly in the cooled crust (the top of the ice cream should be level with the top of the crust). Freeze until solid, at least 3 hours and up to 2 days.
Fill a medium saucepan with an inch and a half of water and bring to a simmer. In the bowl of an electric mixer, combine the egg whites, cream of tartar, and remaining ¾ cup sugar. Place a loosely formed ring of foil in the simmering water, then rest the mixing bowl on the foil (this will keep the bowl afloat and keep the egg whites from overheating). Cook, whisking constantly, until the sugar is dissolved, the mixture feels smooth, and is warm to the touch, about 3 minutes. Transfer bowl to an electric mixer fitted with a whisk attachment, add the vanilla and a pinch of salt. Beat on high speed until peaks are stiff and glossy, 6 to 7 minutes.
Preheat the broiler. Remove the pie from the freezer and spread the meringue over the pie, being sure to spread all the way to the edges so that no ice cream is exposed. Broil until the meringue is lightly browned, about 3 minutes. (Alternately, you can use a kitchen torch to toast the meringue).