Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
In a medium bowl, whisk together flour, cocoa powder, baking soda, and salt.
1 1/2 cups all-purpose flour, 1/4 cup unsweetened cocoa powder, 1 teaspoon baking soda, 1/2 teaspoon salt
In a large bowl, cream together softened butter, granulated sugar, and brown sugar until light and fluffy.
1/2 cup unsalted butter, 3/4 cup granulated sugar, 1/4 cup packed light brown sugar
Beat in the egg and vanilla extract until well combined.
1 large egg, 1 teaspoon vanilla extract
In a small bowl, whisk together the red food coloring and white vinegar. Add this mixture to the butter and sugar mixture. Beat until well combined.
1 tablespoon red food coloring, 1 teaspoon white vinegar
Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined. Do not overmix.
1 1/2 cups all-purpose flour, 1/4 cup unsweetened cocoa powder, 1 teaspoon baking soda, 1/2 teaspoon salt, 1/2 cup buttermilk
Gently fold in the white chocolate chips or chunks, if using.
1/2 cup white chocolate chips or chunks
Drop by rounded tablespoons onto the prepared baking sheets.
Bake for 8-10 minutes, or until the edges are set and the centers are slightly soft.
Let cool on the baking sheets for a few minutes before transferring to a wire rack to cool completely. Serve with a smile!
