In a medium bowl, whisk together the egg yolks, whole milk, and vanilla extract until smooth. Sift in the flour and baking powder, then whisk until you have a smooth, lump-free batter.
In a large clean bowl, beat the egg whites and cream of tartar with an electric mixer on medium speed until foamy. Gradually add the granulated sugar while continuing to beat on high speed until you reach stiff, glossy peaks that hold their shape firmly, about 4 to 5 minutes.
Scoop about one-third of the meringue into the egg yolk batter and stir it in to lighten the mixture. Then gently fold in the remaining meringue in two additions using a spatula, being very careful not to deflate the batter.
Heat a large nonstick skillet over the lowest heat setting possible. Lightly grease it with a small amount of butter. Use a large spoon or piping bag to pile the batter into tall, round mounds about 3 inches wide. You should get 2 to 3 pancakes per batch.
Add 2 tablespoons of water to the pan and immediately cover with a lid. Cook on the lowest heat for 6 to 7 minutes until the bottoms are lightly golden and the pancakes have risen and are set enough to flip.
Very gently flip each pancake with a thin spatula. Add another tablespoon of water, cover again, and cook for another 5 to 6 minutes until cooked through and golden on the second side.
Carefully transfer the pancakes to a plate. Dust generously with powdered sugar and serve immediately with maple syrup and fresh berries. These are best eaten right away as they slowly deflate over time.