Instead of throwing away the leftovers from a nice roast chicken, you can cook it into a broth. This saves you one stock cube, if you’re cynical. It gives you more taste if you’re not.
Eat the chicken until only the bones are left.
Cut a large onion in half. Cut some carrots into pieces.
Put everything into a big pan with enough water to cover the chicken. Stir. Wait. Stir again. Enjoy the aroma. After three to four hours I’m usually left with 1.5—2 liters of excellent broth. I pour it trough a filter into one or two mason jars.