01 - Place vegetable scraps in a large stockpot.
02 - Add bay leaves, black peppercorns, thyme, and salt to the pot.
03 - Pour cold water over the scraps until fully covered.
04 - Heat over high until boiling, then reduce to a gentle simmer.
05 - Simmer uncovered for 1 hour, occasionally skimming off foam.
06 - Remove pot from heat and let cool for a few minutes.
07 - Strain liquid through fine-mesh sieve or cheesecloth into a large container, discarding solids.
08 - Taste broth and adjust seasoning if needed.
09 - Use immediately or cool completely before refrigerating (up to 5 days) or freezing (up to 3 months).