Pre-heat your oven to 220ºC/200ºC fan.

Chop your Cornish new potatoes into bite-sized chunks (usually into 3-4 pieces). Place into a baking tray and drizzle with a little olive oil. Toss the potatoes in the oil so they’re all coated. Lay a few sprigs of rosemary on top. Split the garlic into individual cloves and bash them (either in a pestle and mortar or using the end of a rolling pin) to break them open slightly. Nestle the garlic cloves in between the potatoes and season with salt.

Roast the potatoes for 40-45 minutes, until soft in the centre. Turn the potatoes halfway through your cooking time to ensure they cook evenly.

Once the potatoes are cooked, remove them from the oven then leave to cool to use in your salad.

Mayonnaise is easiest made with a hand-blender, however you can also use a mixer with a whisk attachment on its highest speed setting. The secret to getting mayonnaise with a nice thick texture is to add the oil gradually and ensure that each addition is fully combined before adding more. If the oil is added too quickly the mayonnaise might not thicken.

Put your egg yolks into a bowl or jug and blend using a hand blender. Gradually add the oils, no more than 2 tsp at a time. Blend in each addition before adding more. You mayonnaise will start by looking thin and yellow and as you add more oil it will thicken and it’s colour will become paler.

Once the mayonnaise has thickened, mix in the white wine vinegar/apple cider vinegar.

Take 4 tbsp to use in the potato salad and store the rest in the fridge for another time.

Remove the potatoes from the tray (leave behind the garlic and rosemary) and chop each piece of potato into 2-3 pieces. Place them into a large bowl.

Thinly slice your spring onions (you should use both the white and green bits for this salad) and finely chop the chives. Add them to the potatoes.

Add the mayonnaise, lemon juice, and mustard. Season with salt and mix thoroughly.

Serve.