Boil the potatoes

Wash the potatoes, leaving the skin on. If large, cut in half or thirds.

Tip: don't cut them too small or they might become waterlogged.

Put in a large saucepan, cover with cold water, and season generously with salt.

Bring to a boil then reduce to a simmer and cook until only just tender.

Drain, then leave in the colander or sieve until cool.

If necessary, cut into bite-sized pieces.

Cook the beans (can be done while the potatoes are cooking)

Remove the stems from the beans, cut in half (or bite-sized pieces) and wash.

Put into a saucepan and cover with boiling water from a kettle. Season moderately with salt then bring to a boil. Reduce to a simmer and cook until tender.

Drain the beans BUT RETAIN A FEW TABLESPOONS OF THE WATER FOR THE DRESSING, refresh the beans in cold water, then leave in a bowl of iced water until completely cold.

Drain well.

Make the aioli garlic mayo dressing (make while the potatoes and beans are cooking)

Put the garlic in a mortar along with a small pinch of salt and pound with a pestle until you have creamy paste.

Tip: if you don't have a pestle and mortar, use the end of a rolling pin in a suitable bowl.

Add 2 tablespoons of mayonnaise to the mortar and stir to combine.

Stir in more mayonnaise to reach the right level of garlic flavour for you. Tip: switching to a small silicone spatula at this point makes it easier to combine the ingredients. If you only have a small mortar then you may need to switch to a bowl too.

Stir in 2 tsp of the extra virgin olive oil and add a squeeze of lemon juice, plus a large pinch of black pepper.

Stir in a tablespoon of the bean cooking water (or plain water). If necessary, add more to get a thinnish, light dressing.

Taste and add more salt, lemon, or pepper if needed. If it tastes too strong or is too thin, stir in more mayonnaise.

Put the salad together.

Put the potatoes, green beans and tomatoes into a large bowl and add the dressing. Gently toss to coat the vegetables.

Add the parsley (or other herbs) and gently toss again until thoroughly combined.

Can be eaten straight away or left in the fridge for the flavours to meld.

Best brought back to around room temperature before eating.

The salad will be at its best if eaten within 2 days.