Slice the top of the head of garlic just enough to remove paper and expose the tops of the cloves. Drizzle with olive oil and roast in preheated oven either in a clay garlic roaster or wrapped in aluminium foil. Roast for 20 minutes or until cloves are soft and slip from skins when pushed. Change oven setting to grill ~190 degrees C. Let garlic cool.
Place the chicken in a 20x30cm baking dish and splash both sides with white wine. Grill for 25 minutes or until chicken is cooked through and juices run clear.
Meanwhile, place butter and milk in a large frypan and heat over medium heat until warm. Stir in the flour and cheese. Stir over medium heat until sauce begins to thicken.
Slip cooled garlic cloves from skin and add to the sauce (if desired, mince first). Add diced parsley. Bring nearly to a boil then reduce heat and stir to control thickening.
Pour sauce over cooked rice or pasta then top with grilled chicken.