60 ml (1/4 cup) olive oil
1 onion, chopped
1 clove garlic, chopped
200 g waxy potatoes
2 firm zucchini
1 teaspoon grated lemon zest
20 g (1/3 cup) finely chopped parsley
2 teaspoons each of finely chopped-
fresh marjoram, lemon thyme and thyme
1 teaspoon dried oregano
2 eggs
3 tablespoons cornflour
2 tablespoons sour cream
40 g (1/3 cup) grated emmentaler cheese
2 tablespoons freshly grated Parmesan
2 tablespoons ground hazelnuts