01 - Set the oven to 350°F (175°C) and allow to come to temperature.
02 - Mix graham cracker crumbs, granulated sugar, and melted butter in a mixing bowl. Firmly press the mixture into a 9-inch pie plate, forming an even layer across the bottom and up the sides.
03 - Place the crust in the oven and bake for 8 to 10 minutes, until lightly golden. Remove and cool completely.
04 - In a saucepan, whisk together Coca-Cola, granulated sugar, cornstarch, and a pinch of salt until no lumps remain.
05 - In a separate bowl, whisk whole milk and egg yolks until combined.
06 - Bring the cola mixture to a simmer over medium heat, stirring frequently.
07 - Gradually add a portion of the hot cola mixture into the milk and egg yolk blend, whisking constantly to temper. Pour the tempered mixture back into the saucepan.
08 - Continue cooking, stirring constantly, until the mixture thickens, about 3 to 4 minutes. Remove from heat.
09 - Stir in unsalted butter and vanilla extract until fully integrated and smooth.
10 - Whip 1/2 cup heavy cream to soft peaks. Once the custard has cooled, gently fold the whipped cream in to lighten the filling.
11 - Transfer the cola custard into the cooled crust, smoothing the surface. Refrigerate for at least 4 hours until set.
12 - Whip the remaining 1 cup heavy cream with powdered sugar until stiff peaks form.
13 - Spread the whipped cream over the chilled pie. Top with maraschino cherries for garnish.
14 - Slice and serve chilled.