Preheat oven to 325 °F. Generously brush 12 standard muffin tins with melted butter or line with baking cups.
In a medium bowl, sift together cake flour, baking powder and salt. Set aside.
In another bowl, combine egg yolks, water, sugar and vanilla; whisk until well blended.
Add cake flour mixture to the egg yolk mixture; mix until all ingredients are blended. Stir in vegetable oil and set aside.
Prepare meringue by combining egg whites and cream of tartar in another bowl. Using an electric beater, beat under high speed until egg whites is frothy and bubbly. Gradually add sugar and continue beating until medium peaks are achieved. Fold in the meringue mixture into the batter, a third at a time. Once batter is evenly mixed, fill muffin tins ⅔ full with batter.
Bake mamon in the center of the oven for 15-18 minutes (Mine was perfectly done in 15 minutes). Let cool on racks for 15 minutes.
Carefully run a sharp paring knife around the edges of the muffin tins and gently remove mamon. Serve as is or brush top with melted butter and sprinkle with sugar and grated cheese, if desired.