Prep your pan: Line a baking sheet with parchment paper or a silicone mat. Preheat the oven to 350°F (175°C).
Whisk the dry mix: In a bowl, whisk almond flour, coconut flour, cocoa, sweetener, baking powder, baking soda, and salt until evenly combined.
Cream the fats: In a separate bowl, beat the butter and cream cheese until smooth and fluffy, about 1–2 minutes.
Add the egg and vanilla and beat until just combined.
Add color and tang: Mix in the vinegar and red food coloring. Start with 1 teaspoon of coloring and add more if you prefer a deeper red. The dough will be thick.
Combine wet and dry: Add the dry ingredients to the wet and stir with a spatula until no dry spots remain.
If using white chocolate chips, fold them in now.
Chill briefly: Let the dough rest for 10–15 minutes. This helps the coconut flour hydrate and makes the dough easier to handle.
Shape the cookies: Scoop heaping tablespoon portions (about 1 1/2 tablespoons each) and roll into balls. Place on the baking sheet about 2 inches apart. Gently flatten to about 1/2 inch thick with your palm or the bottom of a glass.
Bake: Bake for 9–12 minutes, until the edges are set and the centers look slightly soft. Do not overbake—they firm up as they cool.
Cool completely: Let the cookies rest on the pan for 10 minutes, then transfer to a rack.
Sprinkle with a pinch of coarse salt or dust with powdered erythritol, if using.