Place the carcass in a large stockpot. Pour enough water in the pan so that it almost covers the bones.
Place the stockpot on high heat.
Add, turkey drippings, carrots, celery, peppercorns, bay leaf, garlic cloves, parsley, onions and kosher salt to taste.
When the stock gets close to a boil, turn to low and simmer the stalk at least 2 hours and up to 6. The longer you simmer it, the deeper the flavors will be.
Strain thru a fine mesh sieve, cool to room temp and refrigerate overnight.
Skim the fat off the next day. Do not be afraid that it looks like jello, that is all the gelatin from the bones.
Stock may be frozen up to 6 months.