Prepare your pan. Generously grease a 12-cup standard muffin tin or line it with paper cases. A silicone muffin tin works best for easy removal.

In a large saucepan, melt the butter over low heat. Add the mini marshmallows and stir continuously with a spatula until they are completely melted and smooth.

Remove the saucepan from the heat. Immediately stir in the semi-sweet chocolate chips and cocoa powder. Continue stirring until the chocolate is fully melted and the mixture is glossy and uniform.

Stir in the vanilla extract. Pour in the crispy rice cereal and fold gently but quickly, ensuring all the cereal is evenly coated with the chocolate marshmallow mixture.

Working quickly, spoon the mixture into the prepared muffin cups, filling each one to the top. Use a greased spatula or your fingers to gently press the mixture down to compact it.

Place the muffin tin in the refrigerator to chill for at least 30-45 minutes, or until the puddings are firm and set.

Once firm, carefully remove the puddings from the muffin tin and place them on a sheet of parchment paper.

In a small, microwave-safe bowl, combine the white chocolate chips and coconut oil (if using). Microwave in 30-second intervals, stirring well between each one, until the chocolate is smooth and completely melted.

Spoon about a teaspoon of the melted white chocolate onto the top of each Rice Krispie pudding. Use the back of the spoon to gently nudge it so it drips down the sides, mimicking the look of brandy sauce or snow.

Before the white chocolate sets, immediately decorate with your festive sprinkles. Add a couple of red candies and green leaf sprinkles to create a holly effect.

Allow the puddings to sit at room temperature for about 15-20 minutes, or until the white chocolate has fully hardened. Serve and enjoy!