Cut broccoli into florets and cook in salted boiling water until soft. Drain and let to cool. Coarsely blend and place in a bowl.
Cut garlic into thin slices and sauté in a little oil. Add EVO oil and sautéd garlic to the broccoli and season with salt.
Clean chicken breasts, removing the central bone and any fat. Heat a non-stick pan and sear chicken breasts only on one side for 3-4 minutes. Transfer to a cutting board and make partial cuts at 1 cm intervals so as to keep chicken breasts in one piece.
Stuff each cut with the broccoli mixture, a slice of fontal cheese and some black summer truffle slices.
Transfer the stuffed chicken breasts to a baking tray, drizzle with EVO oil, cover with foil paper and bake in the oven at 180°C for 20 minutes. Heat the oven grill, remove the foil paper and continue cooking for a few more minutes. Serve with a twist of freshly-ground pepper and fresh rosemary.