In a large mixing bowl or your stand mixing bowl add the Egg Whites, Salt, and Cream of Tartar
Start by lightly mixing everything together (low speed if you're using a hand/stand mixer) until it starts to foam
Once it starts to foam, speed up your mixing (high) and let it continue to mix until it thickens up with a marshmallow texture/you get stiff peaks (this can take anywhere from 5-7+ minutes or longer by hand)
Line a baking sheet with parchment paper
Here is where you can decide how you want your cookies to look by either spooning them, using a dessert decorator, or a piping bag (best)
Whatever method you choose, repeat it until you have all of your cookies on your baking sheet
Optionally top them with anything you want like some sugar free chocolate chips or sprinkles!
Put them into the oven on 250F/121C for 35 minutes
Shut your oven off after 35 minutes and keep them in your oven for around 1 hour
Remove them from your oven and eat or store them!