01 - Preheat oven to 350°F. Combine crushed cookies and melted butter in a medium bowl. Press mixture firmly into the bottom and up the sides of a 9-inch pie dish.
02 - Bake the crust for 8 to 10 minutes. Remove and cool completely on a wire rack.
03 - In a medium saucepan, whisk together milk, cream, sugar, cornstarch, and salt. Cook over medium heat, stirring frequently until the mixture thickens and bubbles, about 3 to 5 minutes.
04 - In a separate bowl, whisk egg yolks. Gradually whisk about 1/2 cup of the hot milk mixture into the yolks. Then pour the yolk mixture back into the saucepan.
05 - Continue cooking and whisking constantly until the filling thickens and just begins to boil, about 2 to 3 minutes.
06 - Remove from heat. Stir in butter, peppermint extract, and optional food coloring until smooth.
07 - Pour the filling into the cooled crust and smooth the surface.
08 - Cover with plastic wrap pressed directly onto the surface to prevent a skin. Refrigerate for at least 4 hours until set.
09 - Beat cold heavy cream, powdered sugar, and vanilla extract until soft peaks form.
10 - Spread or pipe whipped cream over the chilled filling. Garnish with crushed peppermint candies.
11 - Slice and serve chilled.