Preheat oven to 325 degrees.

Cream butter and sugar with mixer until light and fluffy. Add egg yolks, vanilla and sour cream and mix until combined.

Stir baking powder, salt, matcha powder and flour together in separate bowl.

Combine dry ingredients with creamed ingredients and mix until smooth. Place dough onto cookie sheet and press flat, then let rest for 30 minutes in refrigerator.

Roll out dough to ¼" thickness on lightly floured surface and cut cookies with cookie cutter.

Arrange on cookie sheet 2" apart. Make a small pinch at the top of each cookie where the hair will stick up and narrow the sides a bit for the cheeks if you like. Bake for 10–15 minutes, until edges start to brown. Place cookies onto cooling rack.

Mix powdered sugar, water, butter and corn syrup together until smooth. Add more powdered sugar if icing is too runny. Add one drop green food coloring and one drop yellow food coloring and mix well.

Dip the top of each cookie into the bowl of icing, letting the excess icing drip over the sides of the cookie. Let the icing set.

Put white icing in small storage bag and cut a tiny hole in one corner. Using your favorite Grinch picture as a guide, start by making the whites of the eyes with the bag of icing. Attach a red hot to each eye.

Finish each cookie with the black icing by drawing the nose, mouth, crow’s feet, hair and an iris in each eye.