Sift the flour with baking powder and salt in a medium- sized bowl. Using an electric mixer, cream the butter for a full minute, then add the sugar and beat at medium speed until light, about 5 minutes. Beat in eggs and vanilla until fluffy and very light, another 2 to 4 minutes. With a wooden spoon gradually work the flour into the creamed mixture. Divide the dough into two portions and wrap in waxed paper or plastic wrap. Refrigerate until firm, at least several hours or overnight. Heat the oven to 400°. On a floured surface, roll out the dough to inch thick, using more flour for the rolling pin, sprinkled on the dough, and additionally on the floured surface as needed to prevent sticking. Cut into desired shapes with cookie cutters and place on cookie sheets. This dough works beautifully if gathered and rerolled; if it gets too soft, chill for about 15 minutes. Refrigerate or freeze the cut- out cookies on their baking sheets for 10 to 15 minutes so they will retain their firm edges as they bake; if you’re in a hurry, go ahead and bake the cookies immediately. Bake for 5 to 8 minutes or until cookies are puffed and only just barely starting to brown at the edges: Start with the shortest amount of time and watch carefully, especially with very small cookies. As the cookies are fragile right out of the oven, let cool slightly before moving to a wire rack to cool completely. When cool, glaze and decorate as desired. Makes up to 6 dozen cookies, depending on the size. This recipe can be easily doubled or tripled. Sugar Cookie Glaze Whisk the egg white and salt until loosened and beginning to foam. Add oil, confectioners’ sugar, and cream gradually and whisk, adding more sugar and cream until the glaze is of spreading consistency: You want it to be thin enough to spread easily over the cookies to their edges, but not so thin it runs off the sides. Using an offset spatula or a smooth table knife, spread the glaze over each cookie, filling in the shape to its edges. While the glaze is wet, you can decorate the cookies with colored sprinkles, or leave the glaze plain, let dry, and add more decoration with Royal Icing. Royal Icing Before you start, make sure that all utensils and containers are clean and grease- free. Have ready several small containers for dividing the icing and tinting it with different colors, if desired. You will need to keep the royal icing covered with a damp cloth, plastic wrap, or tight fitting lid or it will dry out. Royal icing will keep, tightly covered, in the refrigerator for about one week. This recipe is proportioned for the firmest- textured icing; adjust the texture with the addition of water or sugar as explained below. If using egg whites, combine the egg whites, cream of tartar, and sugar and beat until the icing is thick and holds billowy peaks, about 6 to 8 minutes. Add glycerin for extra shine, if desired. If using meringue powder, whisk the meringue powder and sugar together in the bowl of an electric mixer. Add the water and beat on low speed for about 5 minutes, until icing is thick and holds billowy peaks. Don’t overbeat or the icing texture will become hard to work with. Add glycerin for extra shine, if desired. To adjust the consistency of icing: To thicken, add sifted confectioners’ sugar a spoonful at a time, whisking thoroughly until you reach the desired consistency. To thin, add warm water a few drops at a time, mixing with a spoon. Piped outlines and details require the thickest icing; flows of color over a whole cookie or in sections can be somewhat thinner. Royal icing hardens very quickly when exposed to air, so cover with a damp cloth, plastic wrap, or container lids when not in immediate use. Divide the icing into separate containers for each color to be used. Tint the icing with small amounts of food coloring until it reaches the color desired. To use, icing can be spread onto cookies with an offset spatula or table knife— even painted on with small, previously unused paintbrushes, such as the ones that come in a child’s paint box— or it can be piped through a pastry bag and tips. For simple, plain outlines, use a zipper plastic bag with a tiny hole cut from one corner. Makes about 3 cups of icing.