Gather all ingredients. Preheat oven to 225°F (110°C). Line 2 baking sheets with aluminum foil and grease the foil.
STEP 2
Beat egg whites with cream of tartar and salt in a bowl with an electric mixer until foamy.
STEP 3
Gradually add sugar, a few tablespoons at a time, beating until dissolved before adding more. Continue beating until glossy and stiff peaks form; add vanilla extract.
STEP 4
Spoon meringue into a pastry bag fitted with a small tip.
STEP 5
Pipe meringue into bone shapes on prepared foil. Pipe all shapes at once to prevent deflation.
STEP 6
Bake for 1 hour without peeking. Turn off the oven and let cool inside for 1 hour.
STEP 7
Gently remove cookies from aluminum foil to avoid breaking.