Whisk flour, baking powder, and salt; gradually mix into wet ingredients.
Chill dough for 1 hour.
Roll dough to ¼-inch thickness, cut with holiday cookie cutters.
Place on parchment-lined baking sheets.
Bake at 350°F (175°C) for 8–10 minutes or until edges are light golden.
Cool completely before decorating.
Prepare royal icing: beat powdered sugar, meringue powder, and water until smooth. Tint with food coloring.
Pipe and flood cookies with icing. Let set before serving.
Notes
Chill dough well to prevent spreading.For softer cookies, reduce baking time by 1 minute.Store icing in airtight container covered with plastic wrap directly on surface.