Potatoes and green beans are such a good combination in this salad. You can cook the potatoes whole and chop them up when they’ve cooled or cook them already chopped. I prefer to cook them whole; I think they absorb less water and retain their shape better. If you don’t have Dijon mustard on hand, mixing some yellow mustard with a splash of white wine makes a good substitute.

2 lbs or so potatoes
1 lb or so green beans, tipped, (tailed)
1/2 c chopped green onion, or red onion
1/2 c finely chopped fresh herb
1/3 c broth or stock (use the cooking liquid if you like)
1/4 c extra-virgin olive oil or other oil
1/4 c white wine vinegar or rice vinegar, or other mild vinegar
2 T (Dijon) mustard or other mustard
1 T balsamic vinegar or other red wine vinegar; or use another T of the white wine vinegar
2 cloves garlic, roughly chopped
salt and pepper, to taste

1. Cook potatoes in a pot of (salted) water until just tender. Remove with a slotted spoon to a colander to drain.

2. Return the water to the boil and add the beans. Cook until tender-crisp, or to your preference. While the beans are cooking, chop up potatoes and transfer to a serving bowl, or put already chopped potatoes in a serving bowl. Drain beans, rinse with cold water to stop the cooking, and drain again.

3. Cut beans into roughly 2-inch pieces and add to potatoes. Add green onion. Stir gently to combine.

4. Whisk together the remaining ingredients or whizz in a blender. Pour over vegetables in the bowl, tossing gently to combine. Taste for seasonings.