Ingredient

Kale

Kale is a cabbage that never formed a head. It has thicker leaves and far more fibre than most greens, which is why it stands up to long cooking that would destroy spinach — and why undercooking it or dressing it raw without any preparation produces the chewy, bitter mouthful that put a lot of people off it.

The kales

Curly kale

The common British one. Frilly, robust, slightly peppery, holds dressing well because of all the crevices. Needs the most cooking.

Cavolo nero / lacinato / Tuscan kale

Dark, blistered, strap-shaped leaves. Sweeter, more tender, less bitter. The best of the common kinds and the one to buy if the choice exists.

Red or Russian kale

Flatter leaves with purple stems. Tender, mild, good raw.

Purple sprouting broccoli and kalettes

Relatives rather than kales, cooked much the same way and generally sweeter.

Stalk and leaf are two ingredients

The thick central rib of a kale leaf is dense and fibrous and takes far longer to soften than the leaf around it. Cooking them together gives you either tough stalk or overcooked leaf, and it is the commonest reason kale disappoints.

The usual answer is to strip the leaf off — hold the base of the stalk and pull the leaf away with the other hand, which takes seconds — and discard the rib.

The better answer is to use it separately. Sliced thinly across the grain, the stalk is crunchy and sweet and cooks in a few minutes. Start it in the pan first, add the leaf later, and you have got two textures instead of one problem. It also pickles well, and it goes into stock.

Ways to cook it well

• Long and slow in fat. Sliced kale, olive oil, garlic, a splash of water, lid on, twenty to thirty minutes over a low heat until it collapses and goes silky. This is the Tuscan approach and it is far and away the best thing you can do to cavolo nero.
• Fried hard. Dry the leaves, get the pan properly hot, and let them blister and crisp at the edges. Chilli, garlic, lemon at the end.
• Massaged, for a raw salad. Strip, shred finely, add oil, salt and acid, then rub it between your hands for a minute. It visibly darkens and softens as the cell walls break down, and the difference between massaged and unmassaged kale in a salad is the difference between a good dish and a chore.
• Crisps. Dry leaves, a little oil, salt, spread out in a single layer, low oven until brittle. They burn from one moment to the next, so watch them.
• In soup and stew — ribollita, caldo verde, minestrone, a bean stew. Kale is one of the few greens that improves with a long simmer.
• Blanched then squeezed and chopped, folded into a gratin, an omelette or a pasta filling.

Bitterness, and what to do about it

Kale contains glucosinolates, the sulphur compounds that give all brassicas their character. They are the source of the peppery, faintly bitter note, and how much comes through depends on the variety, the age of the plant and how you cook it.

Three things reduce it reliably. Fat — olive oil, butter, bacon fat — coats the tongue and blunts bitterness directly. Acid — lemon, vinegar — cuts it. And long cooking breaks the compounds down, which is why slow-braised kale is sweet and quickly wilted kale is not.

Frost genuinely helps too. Kale harvested after cold weather converts starch to sugar as a form of antifreeze and tastes noticeably sweeter, which is why it is a winter vegetable in more than name.

Common questions