Preheat the oven to 325 degrees and line a baking sheet with parchment paper.
Beat together the butter and cream cheese until smooth and well combined.
Add the egg and vanilla and beat to combine.
Add the powdered sugar and beat until smooth.
Add the flour and beat until combined.
Place around 1 teaspoon of gel food coloring in the batter and beat until well mixed. Add more food coloring, if needed, until the desired shade of green is reached.
Use a tablespoon to scoop out heaping scoops of dough. Roll the dough between your hands and place it on the lined baking sheet. Slightly press down each cookie.
Bake the cookies for 15 to 17 minutes, until the bottom is lightly browned.
Allow the cookies to cool on the baking sheet for five minutes or until firm, then transfer to a wire cooling rack to cool completely.
When the cookies are cool, lightly dust each cookie with powdered sugar. Place a small drop of red icing on the bottom of each cookie, then press a heart sprinkle into the icing to hold it in place.