Warm the oil in a large heavy-bottomed pan.
Add carrot, parsnip, and celery and sauté over medium heat until they are brown.
Add the remaining ingredients. Turn up heat, bring to a boil.
Partly cover with a lid, turn down heat until the stock is barely simmering and cook for about 45 minutes.
Remove from heat, strain, and add salt and pepper to taste.
If you aren’t going to use it immediately, cool it quickly by placing the pan in a sink full of cold water, before refrigerating.