- Season the radicchio and the Belgian endive with salt and pepper, sprinkle some vinegar and sprinkle some oil on it. Grill at high heat just enough to scald the lettuce and set aside to cool.
- Season the green onions with salt, pepper and oil and grill until scalded, chop ½ inch thick and set aside.
- Sauté the onions in a little oil and butter until translucent, add the diced tomatoes and ½ of the grilled chopped green onions, cook for a minute, season to taste.
- Mix the egg whites well with a whisk, add the cheese and pour onto the onions, mix well and cook the frittata.
- Mix the radicchio, endive, parsley and remaining green onions, season with a touch of olive oil, salt and a splash of vinegar.
- Place the cooked frittata on a plate then top with the radicchio salad.