4 shades of blue food coloring (can be gel or regular)
Preheat oven to 375°F. Pour sugar onto a parchment-lined baking sheet, spreading out evenly. Place in oven for 5-7 minutes until the sugar is heated through but not browned.
Pour the egg whites into a stand mixer fitted with a whisk attachment and beat on low, slowly raising the speed to high. Keep going until you've reached stiff peaks, meaning you can turn the bowl over without the mixture falling out. Be careful not to over-mix. Stop right when you achieve the stiff peaks.
Remove the sugar from the oven. With the machine on high, slowly add in the sugar a little at a time. Keep whisking once all the sugar is added for an additional 5 minutes or so until you have achieved stiff peaks once again, but this time they should be glossy and smooth.
Decrease oven to 200°F and line two baking sheets with parchment paper.
Flip your piping bag inside out and, using a paint brush, make 4 stripes from the tip to the opening of the bag using all 4 colors. They should be evenly spaced around the bag. Flip the bag back and fill carefully with meringue mixture, being sure to pack it in fully to avoid any air bubbles. Pipe drops of meringue onto the baking sheet, leaving some space between them. They should be about 2 1/2 inches wide with a beautiful peak that resembles a raindrop.
Bake for about 2 hours, until the meringues are crisp and can easily be lifted off the paper. The center should be slightly mallowy, but the exterior should be hard and crunchy. Let cool completely and store in an airtight container.