Salt the fillet, pepper, brush with oil. Fry in a well-heated pan (or grill pan) on both sides until cooked.
Finely chop the onion. Heat a small saucepan, pour sugar, keep on fire until caramelized.
Add onions, raspberries, balsamic sauce and rosemary. Keep on fire for 2 minutes, remove rosemary. Salt, pepper to taste.
Put the fillet on a plate, pour over the sauce, sprinkle with crumbled cheese, drizzle with olive oil. Enjoy your meal!