In a bowl mix flour,baking powder,salt and 1 Cup sugar,vegetable oil,egg yolks,4 teaspoons of zest and 150g of tangerine juice,whisk until smooth with a Mixer beat the egg whites with mayonnaise,once a thick foam,add small portions of sugar,when well whipped, pour all the beaten egg whites into the mixture with yolks.

Pour the batter into the form.

Preheat oven to 160 C and bake at the same temperature for 1 hour and 15 minutes,until top has hardened.Turn over,place on a platter

Prepare tangerine impregnation: mix the powdered sugar with the zest. Add tangerine juice. Mix well. Pour the cake impregnated and let stand 1 hour.