Flatten the chicken breasts as much as possible. In a small bowl, combine the oil and garlic and mix together; brush mixture onto each chicken piece. Season with salt, pepper and sage and top with thin layers of prosciutto. Roll up and secure with toothpicks.
In a large frypan, melt butter over medium high heat and saute rolls evenly on all sides until nicely browned, about 10 minutes.
Pour in the wine; season with fresh sage, salt and pepper. Reduce heat to medium low, over and simmer until rolls are cooked through and tender, 15 to 20 minutes. Thicken wine sauce with cornflour and water as needed, heat through and serve.