Halloween Decorated Cookies

Ingredients

• 115 g (1/2 cup) unsalted butter, softened
• 100 g (1 cup) powdered sugar
• 1 egg
• 250 g (2 cups) all-purpose flour
• 25 g (1/4 cup) black cocoa powdered
• 25 g (1/4 cup) Dutch process cocoa powder
• 1 pinch salt
• 1 pasteurized egg white, (about 30g)
• 150 g (1 cup + ½ cup) powdered sugar
• 1/2 teaspoon vanilla extract, optional
• food coloring gel: orange, purple and green