Step 1: Make the Cookie Dough

1. In a large mixing bowl, cream the softened butter and sugar together until light and fluffy, about 2-3 minutes.
2. Beat in the egg and vanilla extract until combined.
3. In a separate bowl, whisk together the flour and salt.
4. Gradually add the dry ingredients to the wet mixture, mixing until a soft dough forms.

Step 2: Chill the Dough

5. Shape the dough into a ball, wrap it in plastic wrap, and refrigerate for at least 1 hour (this helps the cookies hold their shape).

Step 3: Roll and Cut the Cookies

6. Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
7. Roll out the chilled dough on a floured surface to about ¼-inch thickness.
8. Use heart-shaped cookie cutters to cut out the cookies and place them on the prepared baking sheet.

Step 4: Bake

9. Bake for 10-12 minutes, or until the edges are lightly golden.
10. Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

Step 5: Prepare the Icing

11. In a small bowl, whisk the powdered sugar with milk until smooth and pourable.
12. Divide the icing into separate bowls and add red or pink food coloring as desired.

Step 6: Decorate

13. Use a piping bag or spoon to drizzle or spread the icing on the cooled cookies. Add sprinkles or decorations while the icing is still wet.
14. Let the icing set for about 30 minutes before serving or packaging.