This is my favorite curry recipe. I have spent years perfecting it. I originally fell in love with a recipe just like this at a local Lebanese restaurant. As they wouldn't give up their recipe, I went on a mission to copy it.
Combine first group of ingredients into a food processor.
Place chicken pieces in a casserole dish. Add curry sauce, plus 1 to 1 1/2 cans additional coconut milk (depending on how spicy or "saucy" you like your curry). Also add the kaffir lime leaves (left whole), and the lemon grass pieces. Stir, then cover and bake at 375 degrees for 30 minutes.
Remove dish from oven and add mushrooms. Stir well, then return to the oven and bake for an additional 30 minutes (or until chicken is well cooked).