What is the fastest way to recover after a very high intensity workout?

See the answer. Do a cool down immediately. And take it easy for a few hours and when is the time have a good balance meal.
Eat and rest. Postworkout meals after intense exercise should include lean protein and good carbs like sweet potatoes or berries. Protein to help speed the muscle recovery and carbs to replenish glycogen stores. The sooner after you finish the better - optimally within 15 min. Getting enough sleep is also important in helping your body recover between workouts.