In a medium-sized bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt. Mixing these ingredients first ensures even distribution of the cocoa and leavening agents, which helps your cookies achieve the perfect texture.
In a large mixing bowl, use an electric mixer to beat the softened butter and granulated sugar together until the mixture is light and fluffy, about 3-4 minutes on medium speed. Properly creamed butter and sugar create the ideal base for soft and tender cookies.
Add the egg, white vinegar, vanilla extract, and red food coloring to the butter-sugar mixture. Beat everything together until fully combined and the dough turns a vibrant red color. The vinegar reacts with the baking soda to give the characteristic tang and help with the rise.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed just until everything is incorporated. Be careful not to overmix, as this can lead to tougher cookies.
Use a spatula to fold in the white chocolate chips and optional nuts evenly throughout the dough. These add texture and bursts of sweet, creamy flavor that complement the red velvet base perfectly.
For best results, cover the dough with plastic wrap and chill it in the refrigerator for at least 1 hour. Chilling helps the dough firm up, making it easier to handle and helps the flavors meld together.
Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat to prevent sticking and promote even baking.
Using a cookie scoop or tablespoon, drop rounded spoonfuls of dough onto the prepared baking sheet, spacing them about 2 inches apart to allow for spreading. Bake for 10-12 minutes, or until the edges are set but the centers remain soft.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. These cookies are delicious warm but also hold their softness once cooled.