In a bowl, mix together the ricotta,1 egg yolk, 2 egg whites, grated Parmesan, spinach, nutmeg and rosemary. Lay the pre-rolled sheet of puff pastry onto your work surface and brush over the cranberry sauce. Spread the ricotta and spinach mix over, leaving the width of three fingers as a boarder without the filling. Cut the chicken thighs in half and lay them in a straight line down the middle. Roll the pastry up tightly and press together the ends. Place onto a baking sheet and brush all over with the remaining egg yolk. Sprinkle over the sesame seeds and bake at 180°C for approximately 25 minutes or until nicely browned. Allow to rest to cool down slightly before cutting into slices and serving.