Grease a 9-inch pie dish and set it aside.
In a saucepan over low heat, melt the butter and mini marshmallows, stirring until smooth. Remove from heat and mix in the rice cereal, then fold in M&Ms and confetti sprinkles. Press the mixture firmly into the prepared pie dish, shaping it into a crust. Let it cool and set.
In a medium saucepan, whisk together the sugar and cornstarch. In a separate bowl, whisk the egg yolks and milk, then gradually add to the sugar mixture. Cook over medium heat, stirring constantly, until thickened (about 5-7 minutes).
Remove from heat and stir in the butter, vanilla, and chopped chocolate until smooth.
Pour the warm chocolate filling into the cooled Rice Krispie crust. Smooth the top and refrigerate for at least 3 hours until fully set.
Once chilled, top with whipped cream, then garnish with M&M candies, confetti sprinkles, and white chocolate shavings.
Slice and serve this decadent, crunchy, and creamy dessert!
