Snowflake Sugar Cookies

Ingredients

• 3 cups all-purpose flour
• 3 cups bread flour
• 2 teaspoons baking powder
• 1 pound unsalted butter, softened
• 1 cup granulated sugar
• 1 cup packed brown sugar
• 1 teaspoon salt
• 1 tablespoon vanilla
• 1 tablespoon 2 percent milk
• 3 large eggs plus 1 egg yolk
• 1/4 cup meringue powder, such as wilton
• 1 pound powdered sugar
• water, about 1/3 cup
• gel food color