Prep a 9” round cake pan (or you can use a rectangular pan) by lightly spraying it with cooking spray or adding a light coating of butter.
In a microwave-safe bowl, place the butter and 28 regular-sized marshmallows. Microwave on high for 45 seconds. Take the bowl out of the microwave and stir it well. Microwave for an additional 45 seconds. Stir the marshmallow mixture well until it is completely melted and smooth.
Next, add vanilla, red food coloring (4-5 drops for concentrated food coloring and 10-15 drops liquid food coloring), and salt to the bowl and mix it well. The color should be well combined. If the red is not dark enough, add more food coloring.
Spray a rubber spatula with cooking spray and use it to fold in the Rice Krispies until they’re evenly coated with the marshmallow mixture.
Transfer the Rice Krispie mixture into the previously prepared cake pan. Lightly spray the spatula with cooking spray again and press the mixture into an even layer. Set it aside to allow the Krispie treats to set (approx. 30 minutes).
In the meantime, line a large baking sheet with parchment paper.
Cut 50 mini marshmallows and 4 regular-size marshmallows in half.
Once the Rice Krispie mixture is set, carefully remove it from the pan and cut it into 8 wedge-shaped pieces.
Follow the directions on the package to melt the white chocolate melting wafers. Dip one end of each Rice Krispie wedge about 1 inch into the melted chocolate and then place the dipped treats on the parchment-lined sheet.
To create the bottom brim of the Santa hat, place two rows of the mini marshmallows (cut side down) on the white chocolate. Dip the cut side of a halved regular marshmallow into the melted chocolate and put it on the top end of the hat to make the pom-pom. Repeat this process for the remaining 7 Rice Krispie wedges. Let the chocolate set completely at room temperature before serving.