Zero-Waste Cooking: How to Use Every Part of Your Ingredients

**Broccoli stems:** The stems are denser but more flavourful than the florets. Peel the tough outer layer and slice thinly — they stir-fry beautifully, can be shaved into slaws, or diced into soups. Never discard them.

**Cauliflower leaves:** The large outer leaves are edible and delicious when roasted in olive oil until crispy. Treat them like a dark green vegetable — they're similar to kale in character.

**Leek tops (dark green parts):** Too tough to eat raw or in salads, but perfect for stocks, soups and braises where they'll cook for 45+ minutes. Keep a bag in the freezer for stock-making.

**Carrot tops:** Bitter but perfectly edible — use in pesto (replacing half the basil), chimichurri, or as a herb in salads. Wash thoroughly.

**Fennel fronds:** The feathery fronds have a more delicate, sweet anise flavour than the bulb. Use as a herb — on fish, in salads, as a garnish.

**Mushroom stems:** Shiitake stems are too tough to eat but intensely flavourful in stocks. All other mushroom stems can be finely diced and used in fillings, stuffings and sauces.

**Onion skins:** Dry onion skins add colour and flavour to stock. Wash well and add to the stock bag.

Fresh herbs are among the most wasted items in home kitchens — sold in bunches, used for 2 tablespoons, and left to go slimy in the fridge. Professional kitchens use every part and preserve the remainder:

**Herb stems:** Parsley and coriander stems are more intensely flavoured than the leaves. Use them in stocks, add to slow-cooked dishes, or blend into sauces. Only the very thick stems of parsley need discarding.

**Wilting herbs:** Herbs on the verge of going bad can be salvaged by: blending into herb oils (blend with neutral oil and a pinch of salt, strain through muslin, refrigerate for 1 week), processing into herb butter (blitz with softened butter, roll in cling film, freeze), or drying (spread on a tray, leave in a low oven at 60°C for 2 hours).

**Extending fresh herb life:** Treat them like flowers — trim the stems, stand in a glass of water, loosely cover with a plastic bag, refrigerate. This doubles the life of most herbs. Basil prefers room temperature.

**Chicken carcasses and bones:** After roasting a chicken, the carcass and any bones are the raw material for the best possible stock. Simmer with vegetables, water and herbs for 3–4 hours, strain and freeze in portions. One carcass makes 1.5–2 litres of stock worth more than any shop-bought alternative.

**Fish bones and heads:** Fish bones make stock in just 25 minutes — and fish stock (fumet) is the most expensive and hardest to find stock in shops. Ask your fishmonger for frames (carcasses) — often free.

**Parmesan rinds:** The rinds from Parmigiano-Reggiano are a secret ingredient in Italian cooking. Simmer them in soups, stews and ragù — they melt slightly, releasing umami and richness. Freeze rinds and add to any long-cooked dish.

**Bread:** Stale bread has more uses than fresh — breadcrumbs (process and freeze in portions), croutons (cube, toss in olive oil and garlic, bake at 200°C until golden), panzanella (Tuscan bread salad), ribollita (Tuscan bread soup), French toast, bread pudding.