How to make
Sift the flour, baking powder and salt. Beat the eggs in a bowl, add the sugar and beat until creamy.
Pour in the oil and milk, add the vanilla and sifted ingredients. Stir everything very well with a spatula until they're fully absorbed.
You're going to get a thick cake batter. Pour 1/2 the batter into another bowl. Sift the cocoa into it and stir. Smear a cake form with a hole in the middle with a little oil and flour it.
Pour the white mixture into it, pour the cocoa one on top. Swirl a wooden skewer in circular motions over the cocoa mixture in order to distribute it down to the white one.
Put the form in a preheated 340°F (170 °C) and bake to a dry toothpick, about 40 min. Take the ready cake out, remove it from the form and sprinkle with powdered sugar.
