Prepare pasta according to package directions. Drain. Set aside.
Place a chicken breast between 2 sheets of waxed paper. Pound chicken until they are about 1/4-inch thick. Repeat with remaining breasts.
In a small bowl combine flour, oregano, salt and pepper, to taste.
Dredge chicken in flour until coated thoroughly.
Place olive oil and butter in a large skillet.
Place skillet over medium heat.
When skillet is hot, fry chicken breasts until they are almost fully cooked, about 3 minutes each side.
Remove from pan and set aside. Keep pan on heat.
Pour in Marsala wine and deglaze the pan. Make sure to scrape all the brown bits on the bottom of the pan.
Add chicken broth, mushrooms and garlic.
Cook on medium high for about 10 minutes, or until the sauce has reduced by half.
Add chicken breasts back to the pan.
Cook for another 10 minutes. The sauce should become thick.
Serve over pasta.