Combine all ingredients in large Dutch oven or stock pot.
Bring to a boil, then reduce heat to low. Simmer partially covered for 45 minutes; remove lid and simmer uncovered for 30 minutes more.
Allow stock to cool, then pour through a fine mesh strainer into a bowl. Press vegetable scraps against the strainer with a wooden spoon in order to extract as much stock as possible.
Discard solids and store stock in a plastic container or freezer bag.
Notes
If you want to make broth rather than stock, simply season the stock with salt and pepper to taste after it's done cooking.
Keyword: how to make mushroom stock, how to make vegetable stock, Kitchen Scrap Mushroom Stock
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