Melt unsalted butter in a small saucepan over low heat, stirring continuously until liquid. Transfer to a bowl and freeze for about 15 minutes until cold but not solid.

In a mixing bowl, whisk together the chilled melted butter with granulated sugar, brown sugar, and one egg. Add vanilla extract and stir until smooth and creamy.

Carefully add red gel food coloring to the wet mixture and mix thoroughly until evenly distributed.

In a separate bowl, whisk together all-purpose flour, cocoa powder, baking powder, baking soda, and salt until well mixed.

Gently fold the dry ingredients into the wet mixture using a spatula until no dry patches remain.

Preheat your oven to 350°F (175°C). Prepare baking sheets by lining with parchment paper.

Portion the dough into balls about 1.5 inches in diameter and roll each in red sanding sugar.

Place the baking sheets in the oven and bake for 9 to 10 minutes until edges are set and centers are slightly puffy.

Allow cookies to cool on baking sheets for 5 to 10 minutes, then transfer to a wire rack to cool completely.