Never-Fail Sponge Cake - cooking recipe

Ingredients

6 egg yolks
1 1/2 cups sugar
1 1/2 cups all-purpose flour
1 teaspoon baking powder
1/4 teaspoon salt
1 tablespoon vanilla
2 teaspoons lemon juice
1/3 cup room temperature water
1 -2 tablespoon grated lemons (optional) or 1 -2 tablespoon orange zest (optional)
6 egg whites, room temperature
1/2 teaspoon cream of tartar

Preparation

Preheat oven to 325 degrees F.
Set oven rack to second-lowest position).
Prepare an ungreased tube pan with removable sides.
Sift together the flour, baking powder and salt.
In a large bowl beat egg yolks until thick and lemon colored (this is important the egg yolks must be thick, the beating time should take about 5 minutes or more).
Add in sugar, vanilla and lemon juice; beat until thoroughly blended and no sugar granules remain (about 5 minutes).
Add in sifted flour mixture alternately with water; beat until just blended.
In a large stainless steel or copper bowl beat room temperature egg whites with cream of tartar until quite stiff; gently fold into the flour mixture.
Transfer to the ungreased tube pan.
Bake for 55-60 minutes.
Immediately turn the pan upside down and cool completely before removing.