Take a sharp knife, hold the flank steak flat with the palm of your hand and cut an incision lengthwise, continue until you obtain an even flat surface. Season the meat with salt and pepper. Sprinkle with chopped garlic, spinach, olives, sundried, pine nuts and gbejna. Roll the steak like a Swiss roll and tie with a string. Seal the meat in a hot pan in olive oil and butter with the rosemary. Transfer to a baking tray and bake to your liking, (approx. 15-20 minutes for medium) Allow resting before slicing. Mix the mashed potatoes with yolks, nutmeg, parsley and seasoning. Pipe rosettes of the obtained mixture onto a buttered baking tray. Brush with melted butter, sprinkle with the cheese and bake. Serve the steak accompanied with the Duchess potatoes, grain mustard and buttered fresh beans