Preheat oven to 180°C (360°F)
Grease a savarin mould. Beat the eggs, sugar, and vanilla until they triple in volume.
Next, add the oil while continuing to beat, then add the yogurts. Mix well.
Incorporate the baking powder, mix, and then add the 300 g (10.6 oz) of sifted flour.
Divide this batter into two equal portions and place them in two mixing bowls.
Add the 30 g (1.oz) of flour to one of the bowls and mix well.
Add the cocoa to the other bowl and mix well.
Pour half of the plain batter into the mold, then pour half of the cocoa batter on top. Cover with the remaining plain batter, then with the remaining cocoa batter.
Bake for 35 to 45 min. A skewer inserted into the center should come out clean.
Remove from the pan and cool on a wire rack.
The cake rises beautifully. It’s very tall, extremely moist, and spongy. You’ll love it!