Method 1) Royal Icing with Fresh Egg Whites - In a stand mixer fitted with the whisk attachment, add egg whites, vanilla extract, and cream of tartar. Mix on medium-high speed (setting 8) until frothy, about 30 to 35 seconds.Slowly add the powdered sugar. Pulse on and off 8 times to prevent the sugar from going over the bowl. Mix on low speed (setting 2) until combined, about 35 seconds. Scrape down the sides as necessary. Mix on medium speed (setting 6) until it holds a stiff peak, about 4 to 5 minutes. This method yields a texture ideal for making gingerbread houses. For decorating cookies, divide the royal icing into two bowls to make a border and flood icing.
Method 2) Royal Icing with Meringue Powder - In a stand mixer fitted with the whisk attachment, add the powdered sugar, meringue powder, 9 tablespoons of warm water, and vanilla extract. Mix on low speed (setting 2) for 7 minutes. Increase the speed to medium-low (setting 4) and mix until a pipeable peanut butter consistency is reached, about 2 to 3 minutes. Scrape down the sides as needed.This method yields a texture ideal for decorating cookies. If doing so, divide the royal icing into two bowls to make a border and flood icing. However, for a thicker consistency, to use for gingerbread houses, continue to whisk on medium-high (setting 8) for an additional 30 to 60 seconds.
Make Border Icing (for outlining cookies) - The consistency should be similar to pipeable peanut butter. If needed, add ½ teaspoon of water at a time and mix to thin out.
Make Flood Icing (for filling cookies) -Add ½ teaspoon of water at a time and mix until a school glue consistency is reached. If it gets too runny, add more powdered sugar, 1 teaspoon at a time.
Creating Colors - Divide the border and flood icing into small bowls, depending on the desired number of colors. Place a piece of plastic wrap directly on top to prevent them from drying out. Add the gel or liquid colors to each bowl, and mix. Cover with plastic wrap until ready to use.
Outline with Border Icing - Add the border icing to a small squeeze bottle or piping bag fitted with a round tip. Pipe an outline around the edge of the cookies. Allow it to dry until just beginning to set. Once done, if you have leftovers, add them back to the bowl with the corresponding color. Keep the bag or bottle for the flood icing.
Fill with Flood Icing - Add the flood icing to the piping bag or bottle used to make the borders or use a new bag or bottle. Fill in the interior of the cookie design with flood icing, pushing the icing into the corners and against the edges. If needed, use a small offset spatula or toothpick to spread and blend into the outline.
Adding Decorations - Add sprinkles, nonpareils, or other decorations while the icing is still wet. If desired, on completely dried iced cookies, use border icing or edible writing pens to write messages on top.
Drying the Cookies - Place iced cookies on a parchment paper lined sheet pan or on top of wire racks until completely dried, at least 6 to 8 hours. When the cookies are dry, the surface should be smooth and resistant to nicks or smudges.
Notes
Yield: About 2 cups for method one, and 3 cups for method two.
Serving size: 1 tablespoon
If Not Using Immediately: Cover the icing with a damp paper towel, directly touching the surface to prevent it from drying out. Place plastic wrap over the mixing bowl or piping bag tip.
Storing Icing: Transfer any unused icing into an airtight container. Place a piece of plastic wrap directly on top. Store in the refrigerator for up to 3 days. Allow it to come to room temperature before use. Mix on low speed in a stand mixer or by hand with a spoon before using it to smooth out the consistency.
Storing Iced Cookies: Store in an air-tight container for up to one week.