Preheat oven to 350F.
Melt butter with chocolate, set to cool.
Sift together: flour, cocoa, baking powder, baking soda, and salt.
Whisk together: sugar, sour cream, eggs, vinegar, and vanilla. Add red food coloring slowly.
Add butter mixture, mix to combine, and add the dry ingredients.
Drop the batter onto prepared cookie sheet (use ice cream scoop), bake for 12-15.
Once cooled, spread cream cheese frosting on one cookie and sandwich it with another.
Credit: Butter Baked Goods by Rosie Daykin