Preheat the oven to 200 degrees F. Line 2 baking sheets with parchment paper. Set aside.
Pour the egg whites into the bowl of a stand mixer. (You can also use mixing bowls and a hand mixer for this step.) Beat on medium speed until foamy. Add the salt and cream of tartar and beat on high speed.
As the eggs thicken, slowly sprinkle in the sugar, just a bit at a time. Beat the eggs on high until they become shiny and stiff peaks form. When you lift the whisk, the upside-down peak will hold its shape and not droop.
Carefully fold in the lemon zest, vanilla extract, and lemon extract with a rubber spatula.
Place a star tip (or your preferred tip shape) in a piping bag. Fill the piping bag with the meringue mixture. Pipe 1 to 1 ½-inch meringues onto the prepared baking sheets, leaving room in between each cookie.
Bake for 2 hours. Remove the cookies from the oven and allow to cool on the baking sheets.
Notes
If you want to give these cookies a yellow color, you can add a few drops of yellow food coloring when adding in the extracts.