I cut up the carcass, neck and odd bits in smaller 2 or 3 inch chuncks, then put them in the hot oven in a roasting pan, until deep golden brown but not burnt. Then place them in a stockpot, cover with cold water, and slowly bring to a very slow simmer. While that's heating up I roast the aromatic vegetables in the oven (chunks of onions, carrots, celery).
Once the
chicken is simmering you have to skim the top and if possible defat it, with a laddle and/or a skimmer. After a while you can add the roasted veggies, a bouquet garni if using, let simmer a few hours, strain, cool down in ice until room temp, then freeze or chill in the fridge.
You can also rub the
chicken bones with tomato paste before roasting.