Preheat oven to 350°F. Cream butter and sugar in a mixer. Mix in yolk and vanilla, then flour and salt, well. Roll into balls (size of a large marble). Coat in green sugar. Bake on 2 baking sheets for 12 minutes; rotate pans halfway through.
Remove from oven. Lightly indent centers. Push licorice "eyelashes" into cookies; bake for 2 minutes. Push tip of whitechocolate chips into centers. Bake for 3 minutes. Immediately press a mini M&M in center of each chip. Cool.