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What is the tastiest ingredient people routinely throw away?

Chef Sabine Spindler nominates the stems and roots of herbs as the food scrap we should be making much more of. "The roots in particular are often the tastiest part of the plant," says Spindler, who heads up the thrifty kitchens of Sydney's Cornersmith cafes in Marrickville and Annandale.

Cornersmith is at the forefront of the pickling and preserving renaissance, but if jars of bubbling, fermenting foodstuff is just not your thing, there are other ways to get more from your grocery dollar (or backyard harvest).

A simple way to use a whole herb bunch is to process the stems and roots into a curry paste for Asian-style dishes, or as the base for a zesty green sauce to accompany grilled fish or meats.

"Chimichurri is lovely and light and full of flavour," says Spindler. The best thing about it is its versatility. While South Americans typically use it on barbecued meats, she loves to grill or steam fish and drizzle the dazzling green sauce over the top for a really quick, healthy midweek dinner.

How to make chimichurri: Put the stems of parsley and coriander (or any combination of parsley, coriander, mint, basil or even dill) into a food processor with any leaves you're not using in another recipe (including wilted, discoloured). Add vinegar, chilli seeds and cumin to taste, (and garlic if you like). Blitz. Done.

Need a salad pick-me-up? Spindler says brining juice is bottled flavour waiting for a chance to shine. If you're after a sweeter dressing, use the liquid from any bottle of pickled vegetables such as gerkhins, capers (whatever is lurking in your fridge). For a more sour, umami flavoured dressing, the leftover liquid from ferments such as sauerkraut or kimchi work well.

How to make pickle juice dressing: Mix 100ml strained pickling brine with 1 tsp mustard (Dijon, seeded or both). Add some white wine or red wine vinegar if needed. Whisk or blend together, then add 200-250ml oil (Spindler likes to use 50 per cent olive oil mixed with 50 per cent grape seed or good quality canola or sunflower). Emulsify. Add salt if needed. Spindler says these dressings work well with bitter winter greens such as radicchio, rocket or endive.

Make your next batch of winter apples, pears (or any fruit) stretch further.

How to make a fizzy, fruity brew: Mix 2.5 litres water with 400g sugar (and 60ml whey, optional) and pour into a large jar or plastic container. Place the leftover parts of any fruit including cores and skin into the jar and fully submerge. Cover completely with baking paper, then a heavy lid (or plate). Cover with a tea towel and leave at room temperature in a dark spot for five to 10 days. The naturally-occurring bacteria will turn the fruit sugars into a fizzy soda. The flavour will grow stronger with time (and be aware it can turn alcoholic!) When you're happy, strain the liquid and store it in the fridge. Use it as a cordial and mix with sparling water. Spindler loves persimmons this way, and adds some lemon verbena, lemon thyme or even bay leaves.