Place the mushrooms in a medium mixing bowl and toss gently with the salt. Place a plate on top of the mushroom and weigh it down with a heavy object. Let the mushrooms sit for an hour. Drain, spread them on a clean towel and pat them dry.
Bring the vinegar to a boil in a medium saucepan over medium-high heat. Add the mushrooms, return to a boil, and boil until they have softened slightly but still have a nice meaty texture, 3-5 minutes. Drain and spread the mushrooms out on a clean towel and pat them dry. Let them dry until they are no longer damp, about 2 hours.
Combine the oil, mustard seeds, tarragon and lemon zest in a small saucepan over medium heat. Heat, stirring from time to time, to just below a simmer (look for small bubbles to appear). Remove from the heat and let cool slightly.
Place the mushrooms in a wide mouth pint-sized canning jar. Pour the infused oil over the mushrooms, adding more oil to submerge completely if necessary. Cover and refrigerate. To serve, bring to room temperature and remove only what you plan to use. Top the jar with oil as necessary to keep the remaining mushrooms submerged. Eat within 3 months.
Heat the oil in a large stockpot over medium heat until shimmering. Add the turmeric and saute for a few minutes. At this point, you can add the vegetable scraps and saute until browned for a deeper layer of flavor, but it's not necessary. Add the remaining ingredients, cover and bring to a boil. Reduce heat and simmer for 30 minutes. Pour through a fine mesh strainer and transfer to multiple smaller containers (I use quart sized canning jars). Allow to cool to room temperature and transfer to the refrigerator for a few days or to the freezer for up to 6 months.
1) I didn't find the flavor from this amount of turmeric overpowering so you could try adding more if you like; 2) any of the herbs and spices are optional - just use what you have on hand and like; 3) this recipe makes about 8 cups.
Heat oil over medium heat in a 12" non-stick skillet until shimmering. Add the onions, salt and pepper and cook, stirring occasionally, until translucent and just starting to brown, about 5-7 minutes. Add the remaining ingredients and bring to a boil. Reduce to a simmer and cook until almost all of the liquid has evaporated and the mixture is jammy, about 15 minutes. Taste and adjust seasoning as needed. Transfer to an air-tight container and cool to room temperature. Store in the refrigerator for up to 2 weeks.