In a large pan, gently melt the butter over low heat until it's liquid. Stir in the mini marshmallows and keep stirring until they're completely smooth and gooey. Take the pan off the heat, then mix in the vanilla extract. Carefully fold in your puffed rice cereal until every piece is coated in that marshmallow goodness. Let it cool for just 2-3 minutes – it should be warm enough to handle comfortably.
Lightly grease your hands with a tiny bit of butter or cooking spray (this helps a lot!). Now, scoop up small amounts of the mixture and roll them into cute, bite-sized balls, about 1 to 1.5 inches across. If the mix feels a little crumbly, just give it a gentle squeeze to shape. Place your finished balls onto a baking sheet lined with parchment paper and let them chill out until cool.
Grab a microwave-safe bowl and add your white chocolate chips. Melt them in short bursts of 20-30 seconds, stirring well after each burst, until the chocolate is silky smooth. If it seems a bit thick, stir in the optional coconut oil to make it extra dippable. Let the melted chocolate sit for a minute or two; a slightly thicker chocolate coats better.
One by one, dip each crispy ball into the melted white chocolate, ensuring it's fully covered. Use a fork to lift it out, letting any extra chocolate drip off. Place the coated ball back on the parchment paper and immediately shower it with those beautiful red, green, and white sprinkles before the chocolate sets.
Let your chocolate-covered crispy balls set at room temperature. If you're in a hurry, pop the tray into the refrigerator for about 15-20 minutes to speed things up. Once the chocolate is firm, arrange these delightful treats on a serving plate or in an airtight container, ready to share the holiday joy!