Make the Dough: Cream the butter and powdered sugar together until smooth. Add the egg yolk and the black sesame paste, mixing until the dough turns a uniform grey. Fold in the flour until a dough forms.

Chill: Wrap the dough in plastic and refrigerate for at least 30 minutes. Cold dough is the secret to clean edges.

Shape: Roll the dough out to about 1/4 inch thickness. No cutter? Use a glass to cut a circle, then pinch the top two sides to create his pointy ears. It should look like an oval with two little horns.

Bake: Place on a parchment-lined sheet at 325°F (160°C) for 12–15 minutes. Let them cool completely—if they are warm, the "eyes" will melt!

The "Face" Work Eyes: Melt a little white chocolate and dab two circles on the head (or press a white chocolate chip upside down into the cookie while it's still slightly warm). Details: Use a toothpick dipped in melted dark chocolate to draw the pupils, his little nose, and the "Very" shaped markings on his belly.