Pour 9–12 cups of crispy rice cereal into your large mixing bowl. This gives you plenty to work with for an even coating.

Combine white chocolate chips (or candy melts) and peanut butter in a microwave-safe bowl. Microwave in 20–30 second intervals, stirring between each, until completely smooth and melted. Stir in vanilla extract if using.

Split the melted mixture into 2–4 smaller bowls (one per pastel color). Add 2–3 drops of gel food coloring to each bowl and stir gently until you achieve soft pastel shades—think baby chick yellow, cotton candy pink, sky blue, and mint green.

Working with one color at a time, drizzle the colored chocolate over portions of the cereal. Use your spatula to fold and toss gently, coating the cereal evenly without crushing it. Repeat with remaining colors, keeping them somewhat separate for a marbled look (or mix fully for a unicorn effect).

While the chocolate coating is still tacky, sprinkle in candy-coated chocolates, mini marshmallows, sprinkles, and pastel candies. Toss lightly to distribute throughout the mixture.

Spread the coated cereal onto parchment-lined baking sheets in a single layer. Let cool at room temperature for 15–30 minutes, or refrigerate for 10 minutes to speed things up. The chocolate should harden completely.

Once set, use your hands or a spatula to break the mixture into bite-sized clusters. Store or serve immediately.