Whisk the dry ingredients. In a medium bowl, whisk flour, cocoa powder, baking powder, baking soda, and salt until no streaks remain. Set aside.
Cream the butter and sugar. In a large mixing bowl, beat softened butter and 1 cup granulated sugar on medium speed for 2–3 minutes until pale and fluffy.
Scrape the bowl as needed.
Add eggs and flavorings. Beat in eggs one at a time until smooth. Mix in vanilla and vinegar. The vinegar helps create that classic red velvet tang.
Add buttermilk and color. Mix in buttermilk on low speed.
Add red gel food coloring, starting with 1 teaspoon. Blend until the color is even. Adjust to reach a vibrant red.
Combine wet and dry. Add the dry mixture in two additions, mixing on low just until combined.
The dough will be soft and slightly sticky. Do not overmix.
Chill the dough. Cover the bowl and refrigerate for at least 2 hours, or up to overnight. Chilling helps the cookies hold their shape and form bold crinkles.
Preheat and prep. When ready to bake, preheat the oven to 350°F (175°C).
Line two baking sheets with parchment paper.
Set up the sugar bowls. Place 1/2 cup granulated sugar in one shallow bowl and powdered sugar in another. Rolling in granulated sugar first helps the powdered sugar stay put and not melt during baking.
Shape the cookies. Scoop 1 1/2-tablespoon portions (about a heaping tablespoon) of dough. Roll quickly into balls with slightly damp hands.
Double-coat in sugar. Roll each dough ball in granulated sugar to coat, then generously in powdered sugar.
Don’t skimp on the powdered sugar.
Bake. Arrange on the lined sheets, spacing about 2 inches apart. Bake 10–12 minutes, until the tops are cracked and the edges are just set. The centers should look soft.
Cool. Let cookies rest on the sheet for 5 minutes, then transfer to a wire rack to cool completely.
They will firm up as they cool.