1. Preheat the oven to 200°C on the grill function.
2. Chop the onion and grate the potatoes coarsely. Sauté them in an ovenproof frying pan. Reduce to medium heat.
3. Beat the eggs with some salt and pepper. Pour the mixture over the onions and potatoes.
4. When the bottom has set and the top is almost set, top with small pieces of Castello® Double Crème Blue.
5. When the bottom has set and the top is almost set, top with small pieces of Castello® Double Crème Blue.
6. Put the pan in the oven and bake for approx. 10 min. until the top is golden brown and the cheese has melted.
7. Top the frittata with a handful of walnuts, sliced radishes and chives.