01 - Wash and chop carrots, celery, onion, leek, parsnip (if using), and garlic into large chunks.
02 - In a large stockpot, combine the chopped vegetables along with parsley, thyme, rosemary, bay leaves, peppercorns, and salt.
03 - Pour in the cold water, ensuring all ingredients are fully submerged.
04 - Bring to a boil over medium-high heat, then reduce heat to a gentle simmer.
05 - Simmer uncovered for 1 hour, occasionally skimming any foam that rises to the surface.
06 - Remove from heat and strain through a fine-mesh sieve, discarding all solids.
07 - Taste and adjust seasoning if needed. Let cool completely before refrigerating or freezing.