Separate egg whites and yolks into two bowls.
Add milk and vanilla extract to the yolks, whisk until combined.
Sift flour and baking powder into the yolk mixture, whisk until smooth.
Add cream of tartar to egg whites, beat until foamy.
Gradually add sugar to egg whites, beat until stiff peaks form.
Gently fold egg whites into yolk mixture in three additions.
Heat a non-stick pan over low heat, grease with butter.
Scoop batter onto the pan, cover with a lid, cook for 4-5 minutes.
Flip pancakes, cover, cook for another 4-5 minutes.
Serve with maple syrup.