Four measured cups of homemade, deliberately neutral vegetable stock made from roasted mirepoix, mushrooms, rosemary, and oregano.
Prepare & package
Roast the onion, carrots, celery, mushrooms, rosemary, and oregano to develop flavor. Transfer to a stockpot, cover generously with water, and maintain a gentle three-day simmer, adding water as needed to keep the solids covered. Strain out the solids. Do not salt or otherwise season toward a specific final dish. Cool completely, measure into 4-cup bags, vacuum-seal, and freeze.
Store & thaw
Keep frozen in the sealed measured 4-cup bag.
Cook or reheat
Thaw in the refrigerator, reheat from the sealed bag in a controlled water bath, or add directly to a dish when its cooking method permits. Bring fully hot when serving as broth.
Finish & serve
Season, enrich, or reduce only in the final dish; the stock itself is intentionally neutral.