Mix butter and sugar in a stand mixer fitted with a paddle attachment at medium speed until well combined and creamy.

Add the eggs and vanilla and combine.

Whisk flour, salt, and cornstarch together in a separate bowl.

Add the flour mixture to the wet ingredients little by little. Mix at low speed until well combined. Make sure you clean the sides of the bowl, so it is all mixed.

Extend the dough into a sheet that is 1/4” inch thick. Place it on a sheet of parchment paper or an acrylic sheet.

Place the dough in the refrigerator for 30 minutes.

Preheat the oven to 350 degrees. Spray some non-stick spray on a baking sheet and set it aside.

Cut the shapes and place them on a baking sheet.

Bake for 12 to 15 minutes, or until the edges are golden.

Let them cool for at least an hour. They must be completely cool before you add the icing.

In a stand mixer, whisk powdered sugar, flavor extract, water, and meringue powder until it’s fluffy and has peaks in it on medium to high speed. This could take anywhere from 4 to 5 minutes.

Check the consistency of your icing. If it's too thick add more water, very little at a time. For these cookies, you should have a medium consistency. It should take about 15 seconds to disappear. This should work for flooding and details so it should not be runny, to make sure it does not fall through the sides. (Medium royal icing is slightly thinner than piping icing.)

Once you have the consistency you want, place it into a piping bag or you can also use a ziploc bag. If you are using a piping bag, seal it with a knot or with a rubber band.

Cut a tiny edge of the bottom of the bag to use.

Outline each cookie with your icing, and continue making a spiral inwards. Then immediately with a toothpick or a tool spread the icing evenly, smooth it out, and place the eyes on the cookie. Allow it to set before adding the lines. This consistency should allow you to fill in large areas of a cookie surface quickly. Repeat the step of adding it into a piping bag and finish all the cookies.

Continue with your icing and drizzle each cookie with a bit of icing to make it look like the mummy wrapping. Be careful not to cover the eyes.