The calculation in the recipe is for a 16cm (6.30 inch) sponge.
- Punch mint leaves and 20g (0.70 oz) of sugar with a blender.
- Beat the whites with half the sugar until fluffy.
- Beat the yolks with the second half of the sugar until white and increase in volume.
- Add the vegetable oil and ground mint to the yolks, and beat until ingredients are combined.
- Stir the whites to the yolk mass with a spatula (very carefully, upward movements).
- Pour the batter into 2 rings.
- Preheat the oven to 347F (175C). Bake the sponge for about 40 minutes (until dry skewers).
- Cool it in a closed oven for 15 minutes and another 15 minutes in an open oven.
- Then take it out of the rings, wrap with foil and put it in the fridge for 6 hours.