Pound the breasts to about 1/2" - 1/4" thickness between plastic wrap. Dredge them in the flour and salt and pepper lightly, and set aside. Put oil and butter in lg. frying pan and heat to medium. Mince the garlic and saute in the oil/butteruntil light gold in color, then add the chicken and saute until light brown. Chicken is thin so it won't take too long, 7-10 minute Remove chicken to platter and keep warm in 200 degree oven. Saute the mushrooms in the oil/butter mixture for about 3 minute then add the drained capers and chicken broth. Cook another 2 minute Add the Marsala wine (NOT cooking wine), and simmer another 3 min.( to cook off any alcohol), then add chicken and any juices back into the sauce. Simmer 5 minute Mix the cornstarch and water, then stir into the pan juices. Cook for about 3-5 minute to make sure cornstarch is well incorporated. Sauce will be lightly thickened but NOT gravy-like. Return all to warm platter and serve. Taste then add salt and pepper if needed. We like this with al-dente whole wheat thin spaghetti and then dress the noodles with the sauce, and a side of fresh carrots boiled to crisp-tender.