Preheat the oven to 350 degrees Fahrenheit and line two baking sheets with parchment paper.

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

In a large bowl, beat the butter and sugar together until light and fluffy, about 2 minutes, then beat in the egg and vanilla.

Add the dry ingredients to the butter mixture in two additions, alternating with the buttermilk, mixing just until combined after each.

Beat in the gel food coloring until the batter is an even, deep pink with no streaks.

Pipe or spoon the batter into 24 rounds, about 2 tablespoons each, spaced 2 inches apart on the lined baking sheets.

Bake for 9 to 10 minutes, until the tops spring back when pressed lightly and no longer look wet in the center.

Let the rounds cool completely on the pan, about 20 minutes, before filling.

For the filling, beat the cream cheese and butter together until smooth, then beat in the powdered sugar until thick enough to hold its shape when lifted on a spoon.

Spread or pipe a generous spoonful of filling onto the flat side of half the rounds.

Top each with a second round, flat side down, pressing gently until the filling peeks out just past the edge.