Reserved bones of white fish
1 medium onion, roughly chopped
2 garlic cloves, roughly chopped
2 thyme sprigs
2 carrots, roughly chopped
2 celery stalks, roughly chopped (optional)
Scallion trimmings
Cilantro stemsPut all ingredients into a stockpot and add enough water to just cover ingredients. Bring to a gentle boil then reduce to a simmer. Cook for 30 minutes. Strain and cool then refrigerate or freeze.
