Add the butter, cream, and flour to a large mixing bowl and mix until well combined. Cover and refrigerate for 2 hours.

Divide the dough into thirds. Take each portion out of the refrigerator about 15 minutes before you roll it out, but leave the dough in the refrigerator until then.

Preheat the oven to 375°.

Roll each portion of dough to a 1/8-inch thickness. Cut with a 1 ½ inch round cookie cutter. Place the ½ cup sugar onto a plate and then place each cookie in the sugar, turning over to coat both sides. Place the cookies onto a baking sheet that has been lined with parchment paper or a silicone baking mat, leaving them about 2 inches apart. Lightly prick each cookie with a fork several times. Bake for 7-8 minutes (until set) and then transfer to wire racks to cool.

Once the cookies are cooled, make the filling. In a small bowl, cream the butter and powdered sugar together. Mix in the vanilla until well combined and then add the food coloring if desired. If you want to make some red and some green, divide the filling in half before adding the food coloring. Spread about a teaspoon of filling on half of the cookies and top with the remaining cookies to make little cookie sandwiches.