In a mixing bowl, combine the powdered sugar and cream of tartar. Stir well.
Slowly, add the liquid egg whites to the powdered sugar mixture. Stir on low speed. Once combined, turn the speed to medium and whisk for 1-2 minutes, until the icing forms soft peaks.
Add in 1 teaspoon of warm water and flavored extract (optional). Mix until combined.
Distribute the icing into separate bowls, designating one bowl per the desired color. Add in 1-2 drops of food coloring to each bowl. Then, mix with until you achieve the desired hues.
With a swift motion, “paint” brushstrokes onto the parchment paper over a baking sheet. Experiment with different lengths, widths, and patterns. Allow the strokes to overlap for a more dynamic look. If you would like gold icing candy, leave some icing candy plain since you’ll need to paint them gold later. completely dry.
Set aside to dry on the parchment paper. This can take a few hours or overnight, depending on the humidity of your environment. For the gold pieces, brush the reserved icing candies with gold cake paint or luster dust after the icing candies are dry.
Once fully set, carefully peel the icing candies off the parchment paper.