Crispy Cornflake Wreaths

Line a large baking sheet with nonstick foil. Melt unsalted butter in a large saucepan over low heat. Add marshmallows and green gel food color and cook, stirring, until melted and combined. Remove from heat; stir in peppermint extract and cornflake cereal. Using wet hands, form 3- to 4-inch disk shapes on the prepared pan, then poke a hole in the middle using a finger. Working quickly, repeat with the remaining mixture. Scatter with sprinkles or mini M&M's, then leave in a cool place until set, 2 to 3 hours. Store in an airtight container for up to 3 days.