1. preheat oven to 180°c (356°f). 2. Mix 4 eggs, 250g dark chocolate, 160g sugar, 80ml vegetable oil, 1 tablespoon potato starch, and 80g chopped walnuts. 3. Pour the mixture into a 20cm springform pan. 4. Bake for 30 minutes. check with a toothpick; the center should be creamy. if you want it more compact, bake for an additional 5 minutes. 5. Let it cool for 15 minutes in the pan, then remove the ring and let it cool for another 10 minutes. transfer to a plate and serve.