Melt the butter in a large saucepan over low heat.

Add the marshmallows to the melted butter and stir constantly with a wooden spoon until the mixture is smooth.

Add the green food coloring and the vanilla extract, stirring to combine.

Add the cornflakes and stir the mixture constantly until the cornflakes are evenly coated.

Place a large piece of parchment paper on the counter and spray it lightly with cooking spray.

Remove the saucepan from the stove and quickly form the cornflake mixture into wreaths by making a small hole in each mound of the cornflake mixture.

While the cornflakes are still warm, place the red-hot candies atop the wreaths for garnish.