Preheat oven to 325 degrees F. Line baking sheet with parchment paper.

In large bowl with electric mixer or food processor, beat together almond paste, granulated sugar and vanilla until smooth. Add powdered sugar and two egg whites and beat until combined.

Whisk remaining two egg whites in shallow bowl. Place pine nuts on plate.

Shape dough into 1-in. balls, rolling them between your palms. Coat each ball in egg whites, shake to remove excess and roll in pine nuts. Gently flatten balls and arrange on prepared baking sheets at least one inch apart.

Bake for 12 to 15 minutes, until golden brown and set in center. Cool for about 3 minutes on pan, then transfer to cooling rack to cool completely.

Arrange half cookies on work surface, flat side up.

Fill piping bag or large zip-top bag with corner cut off with half of frosting. Starting in center of each cookie, pipe spiral of frosting, leaving slight border around edges.

Place remaining 12 cookies on top, flat side down, slightly off-center to make mouth shape.

Using sharp kitchen shears, cut 12 of the marshmallows into triangles for teeth. Gently press teeth onto front of each cookie.

Cut 12 more marshmallows in half widthwise to make eyes. Dollop small amount of frosting on top of each cookie to adhere eyes and place sliced marshmallow rounds on top. Use piping bag to pipe pupils onto each marshmallow eye.