In a medium mixing bowl, combine the sifted flour and salt.
In a large stand mixer bowl, beat the room-temperature butter and sugar together until light and smooth. You can use a hand mixer if you don’t have a stand mixer.
Add the egg and vanilla extract, then beat again until fully combined.
Add the dry ingredients one-third at a time, mixing well after each addition.
When the dough becomes stiff, knead it with wet hands until smooth.
Lay out plastic wrap and divide the dough into two portions.
Wrap each portion, flatten slightly, and chill in the refrigerator for 3 hours.
After chilling, preheat the oven to 350°F (175°C). On a lightly floured surface, roll out the dough to ¼ inch thickness.
Use Easter cookie cutters to cut out shapes and transfer them to a baking sheet lined with a silicone mat.
Chill the cut-out cookies on the sheet for 5–10 minutes before baking to help them hold their shape.
Bake for 8–10 minutes, then let cool on the baking sheet before transferring to a wire rack to cool completely.
Making Royal Icing
In a large bowl, combine the confectioners’ sugar and meringue powder.
Add water one spoonful at a time, mixing between additions. Add vanilla extract and mix on low speed for 5–7 minutes until shiny.
Separate the icing into several bowls—one for each desired color. Mix in gel colors until you reach the shades you want.
For each color, make two consistencies: thick for borders and thin for flooding.
Transfer ¼ to ½ of the thick icing into piping bags and tie them off.
To thin the remaining icing, add a small amount of water and stir until smooth, then transfer each to separate piping bags.
Decorating Sugar Cookies
Cut the tips of the piping bags for decorating. For thick icing, cut a small ⅛-inch opening; for thin icing, cut 1/16-inch.
Test the icing flow before cutting more if needed.
Outline the cookie shapes with the thicker icing.
Fill in the outlines using the thinner icing.
Use a needle modeling tool to pop air bubbles, spread icing, and refine details.
Use a craft heat gun about 10 inches away to lightly dry the surface for a few seconds, forming a thin crust.
Add Easter sprinkles and let the cookies air dry in a cool place for 2 days before packaging or storing.