Pre heat oven to 350 degrees.
Move rack to middle of oven.
Place muffin liners directly on a pan that is covered with parchment (so bottoms don't get too brown) no need to use muffin pan.
Combine cake flour, sugar, and baking powder in a large bowl with a whisk. Add 2 whole eggs, remaining 4 egg yolks, water, vanilla, oil and mix until blended well.
In another bowl, whip 4 egg whites until frothy, add cream of tartar and whip until medium stiff peaks, want it stiff but not dry.
Take a dollop (heaping dinner tablespoon) and fold into the flour mixture, until no streaks remain. Take the rest of the egg whites and fold into the batter until no streaks remain.
Pour batter into cups 2/3 full (I use an ice cream scoop).
Bake until tops are golden (if needed rotate pan halfway through cooking for even browning) 15-20 minute Or until cake springs back when touched. and toothpick comes out clean.
*For mocha flavor dissolve 1 heaping tablespoon of instant coffee into water before adding to the dry ingredients.