Cut the cheese into 1 cm thick, slightly longer strips. Add flour, egg and breadcrumbs to 1 telelr each. Whisk the egg. Turn the cheese in flour, egg and breadcrumbs one after the other. Wash, halve and core the grapes. Clean and wash lettuce.
Cut radicchio into pieces. Peel onion and cut into whole and half rings. Mix vinegar and 2 tablespoons of oil. Season with salt, pepper and sugar. Mix marinade and prepared salad ingredients. Carefully fry cheese sticks in the remaining hot oil until golden brown and serve with the salad