Cut the potatoes into chunks, leaving the skin on if preferred. Cook the potatoes in a saucepan of gently boiling water for 8-10 minutes, until just tender when pierced with a knife.
While the potatoes are cooking, heat 2 teaspoons of the oil in a non-stick frying pan over medium-high heat. Cook the bacon for 5 minutes, until crisp. Remove the bacon from the pan and set aside.
Add the vinegar, sugar, salt and some freshly ground black pepper to the frying pan and bring to a boil. Pour the mixture into a small heatproof bowl and whisk in the remaining oil.
Drain the potatoes and place in a large bowl. Add the spring onions, dressing and bacon, and gently toss to combine. Serve warm.
Tip: When buying potatoes, check how they are labelled. 'Boiling", "waxy' or 'salad' potatoes are good for salads as they hold their shape when boiled. 'Starchy', 'floury', 'baking' or 'mashing' potatoes are best for roasting or mashing. 'All-purpose' potatoes are good all-rounders.
Variation: Substitute spicy chorizo sausage for the bacon, or toss through some chopped fresh flat-leaf parsley, thinly sliced celery, cooked green peas, or a diced green pear with skin on.
Per serving: 290 calories, 12 g protein, 15 g fat (3 g saturated fat), 25 g carbohydrate (9 g sugars), 3 g fibre, 945 mg sodium