Chicken Rolls with Ham and Cheese

This is a homestyle Spanish dish. I've got it from one of my cookbooks. I didn't have white wine, I used red wine instead. It still tasted good.

Ingredients:

2 boneless, skinless whole chicken breasts, flattened, halved
4 thin slices deli-smoked ham
4 thin slices cheese such as Swiss or Mozzarella (or grated)
Salt and freshly ground pepper
Oil
1 medium onion, sliced
1/4 cup olive oil
1/4 cup dry white wine

Preparation:

Heat oven to 350 F. Place ham and cheese on each flattened chicken breast half. Roll up. Secure with toothpicks. Season to taste with salt and pepper.
Lightly coat bottom of 2-quart baking dish with oil. Spread onion slices over bottom of dish. Top with chicken rolls. Drizzle with 1/4 cup olive oil. Cover with foil. Bake for 10 minutes.
Uncover baking dish. Drizzle with wine. Bake, uncovered, for 15-20 minutes or until chicken is no longer pink. If desired, broil for some minutes until golden. Serve.