Place mixer beaters in a large metal bowl; refrigerate 30 minutes. Cut or tear cake into bite-sized pieces; set aside., Break white chocolate into smaller pieces; microwave at 70% power, stirring after 45 seconds. Microwave until melted, about 30 seconds more. Stir until smooth. Let stand 5 minutes; stir 1/4 cup heavy cream into white chocolate until smooth., In the chilled bowl, beat remaining 3-3/4 cups heavy cream until soft peaks form. Gently fold two-thirds of whipped cream into white chocolate. Stir extract into remaining whipped cream., In a trifle bowl, layer cake and white chocolate mixture, repeating layers. Top with peppermint-flavored whipped cream. Refrigerate, covered, until serving. Sprinkle with crushed candies.