Ingredients

1 1/2 cups all-purpose flour, plus more for dusting 

1/2 teaspoon baking powder 

1/4 teaspoon salt 

6 tablespoons ( 3/4 stick) unsalted butter 

1/2 cup granulated sugar, plus 2 additional tablespoons 

2 tablespoons confectioners' sugar 

1 vanilla bean, split, seeds scraped and reserved 

Finely grated zest of 1/2 lemon 

1 large egg 

Fine sanding sugar, for sprinkling 

2 1/4 cups confectioners' sugar 

7 1/2 teaspoons meringue powder 

Preparation

Preheat oven to 375. Make the cookies: Whisk together flour, baking powder, and salt in a medium bowl; set aside.

Put butter, granulated and confectioners’ sugars, vanilla seeds, and zest into the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until pale and fluffy. Mix in egg. Reduce speed to low. Add flour mixture in 3 batches; mix until combined.

Roll out dough between 2 pieces of floured parchment paper to 1/8 inch thick. Refrigerate until firm, about 45 minutes.

Remove parchment. Using a 3-inch umbrella cutter, cut out shapes. Reroll scraps, and cut out. Space cookies 2 inches apart on parchment-lined baking sheets. Bake until pale golden, 5 to 6 minutes. Transfer cookies to wire racks to cool.

Make the royal icing: Put confectioners’ sugar, meringue powder, and 1/4 cup water into the bowl of an electric mixer fitted with the whisk attachment; beat on low speed 10 minutes. Transfer to a pastry bag fitted with a small plain round tip.

Decorate each cookie with icing, and then immediately sprinkle with sanding sugar.