Turn leftover parmesan cheese rinds into an intense, umami packed parmesan rind stock that's perfect for pasta, risottos, soup base and more.
Add the Olive Oil to your cooking vessel over medium heat and sauté the onion and fennel for about 1 minute. Reduce the heat to medium low, add the garlic, and continue to cook gently for another 7-9 minutes until the onions are translucent. Take care not to brown the garlic as that will make the stock slightly bitter.
Add the cup of wine, increase the heat to medium and reduce it by about 2/3 until it's thick and syrupy. This will take 10-20 minutes.
Add the remaining ingredients and stir until it's all well integrated. Seal your pressure cooker, raise the heat and cook for 1 hour. (in a traditional pot, simmer covered for 4 hours)
Strain the mixture in a large colander before storing. The parmesan broth can be refrigerated for up to 1 week and stored in the freezer for up to 6 months.