1. In a medium bowl, whisk together the flour, baking soda, baking powder, and salt.

2. In a large bowl, beat butter and granulated sugar until light and fluffy, then beat in the egg and vanilla extract.

3. Gradually add the dry mixture to the wet mixture on low speed until just combined.

4. Divide the dough in half, form into disks, wrap in plastic, and refrigerate for at least one hour.

5. Preheat oven to 375°F (190°C) and line baking sheets with parchment paper.

6. On a floured surface, roll chilled dough to 1/4-inch thickness and cut out 2-inch rounds.

7. Place cookies on prepared sheets and bake for 8-10 minutes, until edges are lightly golden.

8. Let cookies cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.

9. To make the filling, beat softened butter until creamy, then gradually mix in the powdered sugar.

10. Add vanilla and 2 tablespoons of cream and beat on medium-high until light and fluffy, adding more cream if needed.

11. Divide the buttercream into small bowls and stir in a drop of gel food coloring into each.

12. Spread or pipe frosting onto the flat side of one cookie and gently press another cookie on top to create a sandwich.