Vegetables

Cut them into similar-sized pieces, toss with a little oil and spread in a single layer on a hot tray. Roast at 220°C, turning once; most mixed trays take 25–35 minutes, but dense roots such as potatoes may need a head start.

Yes: steam or boil them without thawing, following the cooking time on the packet, and drain well. For a stir-fry, add frozen vegetables in small batches to a very hot pan so they do not cool it and turn watery.

Keep leafy vegetables in the fridge, ideally in a loosely closed bag or container, and wash them just before use. Store potatoes and onions in a cool, dark, dry place rather than together in a damp fridge; keep tomatoes at room temperature until ripe.

Look for firm, crisp vegetables with smooth, unshrivelled skins and no wet, mouldy or badly bruised patches. Leafy greens should look perky rather than limp, and carrots and courgettes should feel firm rather than rubbery.

Use aubergine, courgette, peppers and tomatoes for ratatouille, or chop vegetables finely for a quick stir-fry with ginger, garlic and soy sauce. Cut pieces evenly so they cook at much the same rate.

Yes: frozen vegetables are convenient, already prepared and can be cooked straight from the freezer. They work especially well in soups, stews and curries, while fresh vegetables are often better when you want a crisp texture or to serve them raw.