In a metal bowl, whisk egg whites, arrowroot, and lemon extract until medium-firm peaks are formed. SLOWLY add sugar crystals while continuing to whisk until stiff peaks form.
Place mixture in a piping tube/bag with a wide tip…or spoon into a gallon plastic bag and cut off the corner tip. Pipe mixture into mounds onto parchment paper.
Bake for 2 hours. Turn oven off and crack the door, but let meringues remain in the oven and let rest for 30 minutes. Peel parchment paper off the backs of the meringues. Store in an airtight container once completely cooled (otherwise, the heat will steam the the meringues and “melt” them in your container.