Preheat oven to 375 F degrees. Line 2 large baking sheets with parchment paper or a silicone mat. Set aside.

In the bowl of a stand mixer or using a hand mixer on medium speed, cream butter and sugar together until smooth and creamy (about 5-6 minutes). Mix in vanilla and beat until combined, scraping down the sides and the bottom of the bowl as needed. Turn mixer off then slowly add in cornstarch and flour. Turn mixer back on low and beat until the dough starts to crumble and clump together. If dough seems too wet - add more flour (1 tablespoon at a time up to 2 tablespoons). If dough is too wet, add 1-2 teaspoons milk. Turn mixer off and gather the dough with your hands to press the dough down and together while kneading and squishing the dough with your palms to form a big ball. This might take about 2 minutes. The warmth from your hands will soften the dough and form together. Pick off 1" pieces and roll and squish tightly into round cookie dough balls (you can roll them in granulated sugar for an extra crunch and sheen if desired) and place about 1.5" apart onto prepared baking sheets. Make an **indentation with thumb or using a 1/4 teaspoon in the center of each dough ball. Bake in preheated oven until set but still pale & not golden, about 10 - 12 minutes. Be careful not to overbake, as the cookies will continue cooking as they are cooling. Remove from oven and indent center again if necessary. Dough will continue to cook as it cools.

Allow to dry on the baking sheet for 5 minutes then transfer to a wired cookie rack to cool completely. Fill with your favorite jam or decorate with choices below.

Hershey's Kisses thumbprints: once the cookies are baked and hot out of the oven, immediately press a Hershey's Kiss into the center while the cookies are still warm. Do not move and allow to dry. The Hershey's Kiss will stick to the cookie once it is dry.

Turtle Thumbprints - fill with melted caramel squares and cream filling, top with pecan then drizzle with melted chocolate and caramel sauce. Full recipe can be found HERE

For the Nutella M&M's cookies - allow baked cookies to dry then fill with Nutella and top with festive mini M&M's.

For the white chocolate peppermint cookies: Allow baked cookies to dry then fill with melted white chocolate and top with crushed candy canes. Allow to set.

For snowmen cookies: Once cookies are baked and still warm, immediately place a white chocolate melt in the center and bake in the oven for an additional 1 minute just until the chocolate melt sticks to the cookie. Then immediately decorate with blue sprinkles for the eyes, 1 orange jimmies sprinkle for the nose and top with cut black licorice pieces for the eyes and mouth. If the sprinkles and licorice do not stick, place back in the oven for another one minute so they all stick. Remove from oven and allow to dry and set.

**For Rudolph cookies: instead of pressing an indent in the middle when you bake the dough, flatten the dough balls with a glass and then stick on the broken pretzels to form the antlers. Once the cookie is baked, immediately press with a Red Smarties' candy for the nose and cut black licorice pieces for the eyes and the mouth.