Preheat oven to 350 F.

In a small bowl, combine flour and baking powder.

Spray a bundt pan with cooking spray. (You can use a spray with flour in it).

Separate egg whites and egg yolks.

Using an electric mixer, beat egg yolks with 1/2 cup of sugar for 4-5 minutes, until pale and thick. Add 1/2 tsp vanilla, beat to combine.

Add oil and water, beat to combine. Scrape down the sides and bottom of the bowl.

Add 1/2 of the flour-baking powder mixture and beat to incorporate.

Beat egg whites with 1/2 cup of sugar until stiff peaks (4 minutes). Add 1/2 tsp vanilla and beat to incorporate.

Add 1/2 of the flour and fold it into the egg whites using a rubber spatula. Make sure flour is well incorporated.

Pour 1/2 of the egg yolk batter and spread it on the bottom of the bundt pan.

Sift 1 tbsp cocoa powder on top.

Add the egg white batter on top. Spread using a spatula.

Sift 1 tbsp of cocoa powder over it.

Add the remaining 1/2 of the egg yolk batter.

Bake for 40-45 minutes, until toothpick inserted into the yellow part of the cake, comes out clean. Cool inside the pan for 5-10 minutes, then invert onto a cooling rack and let it cool completely. Dust with powdered sugar, before serving.