Resist the temptation to add more ingredients to this simply delicious soup. 4c fish or mild chicken stock 2 stalks lemongrass 2in piece ginger 1 lb cod 4T fish sauce 2t peanut or vegetable oil 2t green curry paste, plus more for garnish if desired 4 garlic cloves 8oz mushrooms, sliced 4oz rice noodles 3…