A good workday lunch has to clear three hurdles: it must be quick to make before you have had enough coffee, it must travel without collapsing into a soggy heap, and it must genuinely taste like something you looked forward to. Mediterranean couscous clears all three. It is built on store-cupboard staples, comes together in the time it takes the kettle to boil and cool, and improves as it sits, which means the version you pack at 7.30am is even better by one o'clock.

Why couscous Works So Well for a Packed Lunch

Couscous is not really a grain in the way rice is — it is steamed durum wheat that has been rolled into tiny granules — and that structure is exactly what makes it lunch-friendly. It does not need cooking in the conventional sense. Pour over boiling water, cover, leave for five minutes, then fork it through and it is done. No hob, no draining, no saucepan to wash.

More importantly, it drinks up dressing without turning to mush. Where pasta can go claggy and salad leaves wilt the moment they meet vinaigrette, couscous absorbs lemon, olive oil and tomato juices and gets softer and more savoury as the morning wears on. That is the opposite of most packed lunches.

The Core Ingredients

For one generous lunch, or two lighter ones, you need the following. Nothing here is exotic, and most of it keeps for weeks.

• 150g fine or medium couscous — medium holds its texture better if you are making it the night before.
• 200ml boiling water, plus a pinch of salt and a small knob of butter or a teaspoon of olive oil.
• Half a cucumber, deseeded and diced — scooping out the watery centre is the single best defence against a soggy lunch.
• 200g cherry tomatoes, halved or quartered, so their juice seasons the grains.
• A good handful of black olives, roughly chopped. Kalamata-style ones give the most flavour for the least effort.
• Half a small red onion, very finely sliced, or two spring onions.
• A large handful of flat-leaf parsley, chopped, plus mint if you have it.
• 100g feta, crumbled, or a handful of chickpeas if you want it dairy-free.

The Lemon Dressing That Holds It Together

Whisk the zest and juice of one unwaxed lemon with four tablespoons of good olive oil, a teaspoon of Dijon mustard, half a crushed garlic clove, a pinch of caster sugar, and plenty of salt and black pepper. The sugar is not there to make it sweet; it takes the hard edge off the lemon so the dressing tastes round rather than sharp. Shake it all in a jar if that is easier — it will keep in the fridge for three or four days, so make double and you have next week's lunch sorted too.

Ten Minutes in the Morning

Put the couscous in a bowl with the salt and butter, pour over the boiling water, cover with a plate and leave it for five minutes. While it steams, chop the vegetables and herbs and shake the dressing. Fluff the couscous with a fork, breaking up any clumps, then tip in the cucumber, tomatoes, onion, olives and herbs and pour over the dressing. Toss well, fold through the feta last so it stays in distinct creamy crumbs rather than disappearing, and taste it. It will almost certainly want more salt and another squeeze of lemon than you think.

Seasonal Swaps Through the Year

The basic formula — grain, something juicy, something salty, something herby, sharp dressing — stays the same all year, but the details should follow the seasons.

• Spring: add blanched asparagus tips, broad beans and a little chopped dill.
• Summer: roast or grill courgette and peppers, or simply add chunks of ripe peach or nectarine with torn basil.
• Autumn: fold in roasted butternut squash, a pinch of cumin and pomegranate seeds.
• Winter: use roasted red pepper from a jar, a spoonful of harissa, chopped preserved lemon and extra parsley.

Roasting a tray of vegetables on a Sunday evening is the quiet trick behind most good weekday lunches. Whatever you roast, roast a little extra and it becomes Monday's and Tuesday's couscous without any further thought.

Packing It So It Still Tastes Fresh at One O'clock

Use a container that seals properly, and keep the dressing separate if you are making it more than a day ahead — add it in the morning. Press the couscous down lightly so there is less air trapped inside, then chill. Take it out of the fridge as you leave the house; it will be at room temperature by lunch, which is when couscous tastes best. If your workplace is warm, an ice block in the bag keeps things safe, particularly if you have added feta or any cooked meat.

Eat it straight from the tub, or spoon it into a wrap with a little yoghurt and a handful of rocket. Either way, it beats a limp sandwich, and it costs a fraction of what you would spend at a counter. Once you have made it twice, you will stop measuring altogether — and that is exactly the point.