Preheat oven to 375 degrees F. Line two baking sheets with parchment paper.
In a medium bowl, whisk the flour, cocoa powder, baking soda, and salt until combined.
In the bowl of a stand mixer, beat the butter and brown sugar for 2 minutes using the paddle attachment until light. Add egg and beat again.
Alternate adding the flour mixture with the buttermilk, vanilla, and red gel food coloring, beating after each addition and scraping the sides of the bowl, just until combined. Stir in chocolate chips.
Use a small scoop to drop batter onto the parchment-lined baking sheets, spacing them 2-3 inches apart.
Bake for 10 to 12 minutes, until just done around the edges and the tops bounce back when lightly touched. Cool on the baking sheet for 5 minutes before transferring the cookies to a wire cooling rack to cool completely.