Combine powdered sugar, meringue powder, and salt in a large bowl or stand mixer. Add 6 tablespoons of water and beat on medium speed until fluffy, about 5 to 6 minutes.,Add extracts and beat an additional 2 to 3 minutes until stiff peaks have formed. Transfer to a resealable container until ready to use. Refrigerate up to 7 days.,When ready to ice cookies, color icing if desired. Divide thick icing into number of bowls needed for colors you're mixing. (Pro Tip: to make sure colors match, color thicker icing before thinning out for the flooding icing.),To thin out icing for flooding or filling in borders, transfer portions of colored thick icing to separate bowls and thin out by whisking in water, 1/2 teaspoon at a time. The consistency should spread out slowly like honey.,To decorate the cookies, use the thicker icing to form a border for roll out cookies, make gingerbread houses or create designs on cookies. Place the icing in a pastry bag or use a zip top bag and snip the corner.,To flood or fill in outlined cookies, use thinned-out royal icing and place in a pastry bag. Fill in the outlined cookies, using a toothpick to fill in any holes. If using sprinkles, add while icing is wet.