Cut the king oyster mushrooms in half lengthways or into quarters, depending on their size, and place them in a bowl. Mix half the parsley, thyme, balsamic vinegar, olive oil and crushed garlic together well, seasoning with salt and pepper to taste. Mix the marinade thoroughly with the mushrooms and leave to marinate for about 30 minutes. For the dip, mix the remaining parsley with the sour cream and season to taste with salt and pepper. Grill or fry the king oyster mushrooms for 3–5 minutes on all sides.