Prepare the Butter Mixture: In a large bowl, mix the melted butter, powdered sugar, cinnamon, nutmeg (if using), vanilla extract, and a pinch of salt until smooth and well combined.
Coat the Cheerios: Add the Cheerios to the bowl and gently toss until they are evenly coated with the butter mixture.
Serve Immediately: Transfer the hot buttered Cheerios to a serving bowl. If desired, sprinkle with additional powdered sugar and colorful sprinkles for a festive touch.
Optional Baking: If you prefer a crunchy texture, preheat your oven to 350°F (175°C), spread the coated Cheerios on a baking sheet, and bake for about 5-7 minutes, stirring halfway through. Allow them to cool slightly before serving.