Why roasting beats boiling

British asparagus has a famously short season, running from late April until midsummer's day, and those first bundles of fat, grassy-green spears are one of the true pleasures of the spring kitchen. The trouble is that asparagus is easy to ruin. Drop it into a pan of boiling water and within two minutes the tips collapse, the flavour leaches out into the water, and you are left with something limp and slightly sad.

Roasting is a far kinder treatment. Dry heat drives off moisture, concentrating the natural sugars so the spears taste sweeter and more intensely of themselves. The tips catch and crisp, the stalks stay tender but still hold their shape, and the whole thing happens on one tray while the oven is on anyway. Roasted asparagus also keeps its structure long enough to sit in a salad without turning to mush, which is why it is the version I reach for all spring.

Choosing spears and getting them ready

Look for spears with tight, closed tips and a slight sheen, and give the bunch a squeeze — they should feel firm rather than floppy. Thin spears cook in a flash and suit quick weekday lunches; thick ones are sweeter, meatier and stand up better to potatoes, pastry and grains.

To prepare them, rinse under cold water and trim the woody bases. The classic trick still works: hold a spear near the middle and bend until it snaps, and it will break at the natural point where tenderness gives way to fibre. If the ends look dry and pale, simply cut an inch off instead. Very thick stalks benefit from peeling the bottom third with a vegetable peeler, but leave thinner spears alone. Keep the trimmings in a bag in the freezer for soup or stock.

The one step people skip: dry the spears thoroughly after washing. Wet asparagus steams in the oven rather than roasts, and you lose the browning that gives it its charm.

The basic roast: heat, oil and timing

Preheat the oven to 200°C fan (220°C conventional, gas 7) and slide a large baking tray in to heat for ten minutes. A hot tray gives the spears a head start on colour.

• Toss the dried spears in a bowl with about a tablespoon of rapeseed or light olive oil, a good pinch of salt and plenty of black pepper. You want a thin, even coating — not a pool of oil.
• Spread them on the hot tray in a single layer, with a little space between each spear. Crowding steams them.
• Roast for 8 to 12 minutes, turning once halfway. Pencil-thin spears will be done in 6 to 8 minutes; fat ones may need 12 to 14.
• They are ready when the tips are browned in patches and a spear bends with a little resistance rather than flopping.

Set a timer for the shorter end of the range and check. Ovens vary wildly, and asparagus goes from perfect to overcooked in about ninety seconds.

Flavours that flatter roasted asparagus

Asparagus is generous with other ingredients, so it is hard to go wrong, but a few combinations are worth keeping in your head. Lemon zest grated over the tray while the spears are still hot is transformative; so is a squeeze of juice at the table. Sliced garlic should go in for the last two minutes only, or it will burn and turn bitter.

Beyond that, think about contrast: something salty, something rich, something sharp, something crunchy. Toasted hazelnuts or flaked almonds, grated hard cheese, a soft-boiled egg, a spoonful of mustardy dressing, torn mint or dill, thinly sliced spring onion or chives. Sherry vinegar or white wine vinegar works better here than balsamic, which tends to bully the delicate green flavour.

From tray to table: three light lunches

• Warm potato and egg salad. Boil small new potatoes until tender, halve them, and toss while warm with a dressing of three parts olive oil to one part lemon juice, a teaspoon of Dijon mustard and salt. Fold through the roasted asparagus, top with halved soft-boiled eggs and a scatter of chives.
• Asparagus and ricotta tart. Lay a sheet of ready-rolled puff pastry on a lined tray, score a border an inch in from the edge, and spread the middle with ricotta beaten with lemon zest and black pepper. Arrange the roasted spears on top, scatter over a handful of blanched peas, and bake at 200°C for 18 to 20 minutes until the pastry is golden and puffed.
• Grain bowl with smoked fish. Cook pearled spelt or barley, dress it while warm, and pile in roasted asparagus, flaked smoked trout or mackerel, a handful of rocket and a spoonful of yoghurt loosened with lemon.

Kitchen skills worth practising

The single most useful habit here is dressing late. Roasted asparagus softens quickly once it meets acid and oil, so keep the dressing separate until the moment you serve. A good everyday ratio is three parts oil to one part acid, with a little mustard to emulsify it and salt to sharpen it — taste it on its own before it goes anywhere near the food.

Leftovers are worth planning for. Roasted asparagus keeps for two days in a lidded container in the fridge; eat it cold in a salad, fold it into a frittata, or blitz it with a little stock and cream for a vivid spring soup. Refresh cold spears in a hot frying pan for a minute if you want the edges crisp again.

Above all, cook it more often than you think you should while the season lasts. Six weeks of the year is not long, and a hot oven, a generous pinch of salt and a squeeze of lemon will do more for British asparagus than any complicated recipe.