Rinse and slice zucchini.
Heat oil and butter in a pan and sauté the onions. Add zucchini and fry for 5 minutes. In a bowl, whisk eggs and cream thoroughly, season with 1/2 teaspoon salt and pepper.
Season zucchini slice mixture with salt, pepper and chile peppers.
Pour the egg-cream mixture into the pan and leave everything covered over low heat for 15 minutes.
Pour boiling water over sprouts in a colander and drain well. Mix yogurt with dill, parsley and orange juice.
Peel and add garlic (squeezed through a press) with salt and pepper to taste.
Arrange the sprouts on the frittata and serve with the yogurt sauce.