Preheat the oven to 350°F . Line baking sheets with parchment paper or silicone baking mats.

In a medium bowl, combine the flour, cocoa powder, baking soda, and salt. Set aside.

In a large mixing bowl, beat the butter and both sugars on medium speed until light and fluffy, about 2–3 minutes.

Mix in the egg until fully incorporated. Add the vanilla extract, vinegar, and red food coloring, mixing until evenly combined.

Gradually add the dry ingredients to the wet mixture, mixing just until combined. Avoid over mixing to keep the cookies tender.

Scoop 1 1/2 tablespoon-sized portions of dough and roll into balls. Place them on the prepared baking sheet about 2 inches apart.

Bake for 13 minutes. The cookies will spread, and the centers will look soft but set. Do not over bake. They will firm up as they cool.

Allow the cookies to cool on the baking sheets for 4–5 minutes before transferring to a wire rack to cool completely.

In a large mixing bowl, beat the cream cheese and butter until smooth and well combined.

Add half of the powdered sugar and mix until incorporated.

Mix in the vanilla extract, then add the remaining powdered sugar and blend until smooth.

Use a piping bag to pipe the frosting onto half of the cookies.

Pipe frosting onto one cookie at a time, then top with a second cookie to create a sandwich. You can also use a spatula to spread the frosting on if desired.

Refrigerate the cookie sandwiches until ready to serve. Bring to room temperature before eating.