I hated maths as a kid, and I still do. But there are occasional moments when it comes in handy in the kitchen, especially in solving that never-ending problem of what to make for lunch or dinner. My solution is meal maths, and the equation goes as follows: vegetables + store-cupboard pulses + dressing = triumph. Last week, that involved combining pre-cooked lentils with slow-roasted vegetables and a perky, hot lemon dressing. It’s an endlessly adaptable recipe that’s worth stocking the cupboard for (and sharing with you).

Puy lentil and roast vegetable salad

I love this particular combination of vegetables, but you could use anything you’ve got in the fridge, really: carrots, cabbage, aubergines, cauliflower and courgettes would all work, too. Just make sure you start with roughly 1kg of vegetables.

Prep 10 min

Cook 40 min

Serves 4 as a light meal

1 aubergine

3 red peppers

8 banana shallots

4 garlic cloves

7 tbsp olive oil

1 tsp dried marjoram

1 tsp dried oregano

1½ tsp salt

1 lemon, juiced

1 tsp chilli flakes

150g frozen peas, defrosted

2 x 250g packs pre-cooked puy lentils – to my mind, Merchant Gourmet’s are some of the finest you can buy

Heat the oven to 180C (160C fan)/350F/gas 4. Chop the aubergine and peppers into roughly 2cm x 4cm, bite-sized chunks, then put in a large bowl that’s pretty enough to serve the final salad in. Top and tail the shallots, take off and discard the skins, then quarter them and add to the bowl.

Roughly crush the whole, unpeeled garlic cloves with the back of a knife, and add to the bowl with four tablespoons of the oil, the marjoram, oregano and a teaspoon of salt. Mix everything with your hands until all the vegetables are coated in herby oil, then tip out on to two roasting trays (don’t wash up the bowl – you’re going to re-use it later). Gently pat down the vegetables, so they sit in one even layer, then roast for 40 minutes, stirring once halfway through.

While the vegetables are cooking, make the dressing. Pour the remaining three tablespoons of oil into the salad bowl, add the lemon juice and chilli flakes, and mix well.

Lift the garlic cloves from the roast vegetable trays, squeeze out the flesh on to a board, then roughly chop and stir into the dressing. Add the peas to the salad bowl, and toss to mix.

If you’d prefer to eat the salad warm, heat the lentils according to the instructions, otherwise just tip them straight from the packet into the salad bowl, add the roast vegetables and remaining half-teaspoon of salt, toss and serve.