Finely crush Oreo cookies using a food processor or by placing them in a sealed plastic bag and crushing with a rolling pin. Mix crushed cookies with melted butter using a fork until combined. Press the mixture into a 9-inch pie plate to form a crust. Refrigerate for at least 30 minutes.

In a saucepan, combine marshmallows and milk over low heat. Stir until marshmallows are melted and the mixture is smooth. Remove from heat.

Add red food coloring, peppermint extract, vanilla, and salt to the marshmallow mixture. Stir well.

Cool the mixture for 30 minutes, stirring occasionally.

Fold in whipped cream gently. Pour the mixture over the prepared crust. Refrigerate the pie covered overnight.

Serve the peppermint pie chilled, garnished with extra whipped cream and peppermint candies if desired.