Prepare the Egg Whites: If using raw egg whites, ensure they are fresh and pasteurized for safety.
Mix: In a mixing bowl, beat the egg whites with whisk attachment on medium speed until frothy.
Add Sugar: Gradually add the sifted powdered sugar, mixing on low speed until combined. Bring the mixer to high speed and beat until the icing holds stiff peaks (about 5-7 minutes).
Add Flavor: If desired, mix in the lemon juice, vanilla extract, or almond extract.
Adjust to the Right Consistency: If you need a thinner consistency for flooding, add a few drops of water. For thicker icing, add more powdered sugar.
Use or Store: Use immediately or cover with a damp cloth, wet paper towel, plastic bag, or piece of plastic wrap to prevent drying out. If dyeing the icing different colors, then divide a little bit of the icing into smaller bowls and add the desired natural colors or gel food coloring. If storing, keep it airtight in the refrigerator for up to a week.