Preheat oven to 300° F.
Line a baking sheet with parchment or a silicon sheet.
Beat eggs until foamy. Add salt and cream of tartar. Add sugar a tablespoon at a time, beating eggs until stiff.
Fold in vanilla.
Fill a a pastry bag or resealable bag with the whipped egg mixture. Cut the tip (or corner) and pipe the whipped egg mixture onto the prepared cookie sheet. (Alternative method: Use teaspoons to drop mixture onto cookie sheet.)
Sprinkle topping of your choice onto each cookie.
Bake for 30 minutes and then turn off the oven. Leave the cookies in the oven for 30-45 minutes to allow them to dry.