About an hour or less at 350 F. I just stab them with a fork to see if they are done- I start checking around a 45 minutes. I normally put them in the oven while the meal is resting and then take them out at desert time.
I put mine in a baking dish (uncovered) with about an inch of water in the bottom, with the middles cored out and the raisins packed down in the centers, a layer of cinnamon after about half the raisins are in, and then some cinnamon sprinkled on top of the apples when they are full of raisins. Nutmeg, cloves, and ginger are good too, but cinnamon by itself is just dandy.
Just as a note- one of the best parts is to drink the apple water in the bottom of the pan. It's like a light cider. It is soooo good hot- I actually serve it in mugs.