powdered egg whitesI used Just Whites, in the baking aisle
gel food coloringthe liquid kind won't work well
waxed paper or parchment paper
You will use about 1 cup of confectioner's sugar for each color sprinkle you want to make. You can prepare each color separately or make them all at once if you have multiple bags etc. I did one at a time.
Sift 1 cup sugar into a small bowl. Sifting is important to avoid lumps that can clog your tip later.
In a separate little glass, mix 1 tsp of the dried egg whites with 1 Tbsp warm water. Whisk until the egg whites are completely dissolved. Add to the sugar along with the vanilla and mix it together. Add a little bit more warm water until you get a thick but pipeable consistency. It should not be stiff, but it should not be too thin. Keep mixing until it is completely smooth.
Add in your gel food coloring. Start with a little for pastel colors, more for intense colors. The colors will dry slightly lighter than they look when wet. Mix the color in completely, no streaks.
Spoon the frosting into a piping bag and twist the bag to force the frosting toward the tip.
Pipe out long lines of frosting onto the waxed paper. Don't let the individual lines touch each other. Keep your tip slightly above the paper as you glide down and pipe your line. Don't worry about keeping the line straight, it doesn't matter, but try to keep an even pressure on the bag. If the tip clogs, use a toothpick to clear it, or remove it and wash it out.
Do this for all the colors and then let them air dry overnight. Don't try to move the waxed paper, leave them as is.
The next day when your piped frosting lines are completely dry, cut them into little pieces. The frosting will be very brittle, just nudge the lines together, lining them up as if you were cutting chives, and slice them in small pieces. Don't worry about being too precise.
https://theviewfromgreatisland.com/sprinkles/ March 14, 2013