Into a large
stockpot (or
instant pot), fill with roughly peeled and chopped carrots, celery, onion, parsnips, turnips, leeks, lemongrass, a whole head of garlic chopped in half, fennel fronds (optional), 1 tablespoon of peppercorn, few sprigs of fresh parsley, few sprigs of
thyme, 2 bay leaves, and the roasted chicken parts.