I made this cake once for an office party. My boss wanted to know where I bought it from. He was shock when he found out I made it myself. Now every year for hes Birthday he says "I only want the marble cake & I'll be happy the rest of the year." So I make it every year just for him...
Heat oven to 350F. Lightly grease & flour 2 round 8 inch cake pan.
beat egg whites, gradually add 1 cup sugar beat until stiff & glossy.
In medium bowl sift together the flour, baking powder, salt & the rest of the sugar. Add the oil 1/2 of the milk, vanilla & beat on medium speed for 1 min. make sure to scrape the bowl. Gently fold in the egg whites to batter. Make sure not to over fold.
Add in the remaining milk, egg yolks & beat 1 min more. Remember to scrape down the bowl.
Measure out half of the batter into another bowl. In the other bowl mix together to cocoa powder & hot water until smooth. Combine the cocoa mix with 1/2 of the batter.
Then pour the white batter in the bottom of both pans, then carefully pour the cocoa batter on top of each. keep repeating with both batters until all batter is gone.
Bake for 30 to 35 mins. Cool well on wire rack & frost as you wish.
Note: Sometimes I use a chopstick & mix it around a bit before baking.