Melt 1 cup of butter over low heat until silky and smooth, then cool to room temperature.

Combine cooled melted butter with 1 cup granulated sugar and 1 cup dark brown sugar. Whisk until smooth, about 2 minutes.

Whisk in 1 whole egg, an additional egg yolk, and 2 teaspoons of vanilla extract until fluffy, about 3 minutes.

Whisk together 2 cups of all-purpose flour, ¾ cup unsweetened cocoa powder, 1 teaspoon baking powder, ½ teaspoon baking soda, and ½ teaspoon salt. Fold into the wet mixture.

Cover the dough with plastic wrap and refrigerate for at least 30 minutes.

Preheat your oven to 350°F (175°C). Scoop dough and roll into balls, then flatten slightly on a parchment-lined baking tray.

Bake for 9-10 minutes, until edges feel firm but centers remain soft.

Mix 1 cup powdered sugar, ½ cup room temperature butter, and 2 tablespoons of milk until smooth and fluffy.

Spread frosting on each cooled cookie and decorate with candy eyes and drizzled chocolate.