Crush or break up the carcass and put into a stockpot or large pan with 2 quartered onions. Don’t peel the onions as the skin gives the stock a good colour.
Add 2 chopped large carrots (washed but not peeled) 2 chopped sticks of celery and add a sprig of thyme, a bay leaf and a few parsley stalks or 2 bouquet garni bags (bouquet garni can be bought in the supermarket where you find the herbs). Add several black pepper corns (ground black pepper can make the stock bitter). Add water to cover all ingredients and bring to the boil.
Reduce the heat to a gentle simmer and half cover the pan then simmer for about an hour and a half to 2 hours. Check the liquid does not run too low, top up if necessary.
Leave to cool down and then strain the stock through a fine sieve into an appropriate bowl or container and cover. Discard the carcass and solids (I wrap it in newspaper) into your food waste bin. When completely cold put in the fridge overnight.
Remove and dispose of the solidified fat that will form on the top of the stock. Use the stock within 3 days or freeze in half litres to be used in the next 3 months.
Useful tips –
Keep a bag in the freezer for your stock of onion skins, bits of carrot, celery or mushroom, left over herbs etc rather than put them in the waste.
If you defrost some stock and don’t use it don’t throw it out just bring it back to the boil for a few minutes, cool and refreeze it for another day.
Always label anything in the freezer including the date.
I hope you will find making use of what might otherwise be waste satisfying.
The Tidy Gardener