Place the potatoes in a large saucepan and cover with cold water. Cover and bring to the boil over high heat.
Remove the lid and boil for 25 minutes or until the potatoes are just tender when tested with a skewer. Drain in a colander and set aside to cool slightly.
Add mayonnaise, Dijon mustard, lemon and spring onions in a bowl, mix to combine and set aside.
When the potatoes are cool enough to handle, cut into large chunks. Place in a large bowl and place in the fridge for 20 minutes or until cooled to room temperature.
To serve, transfer the potatoes to a serving bowl and stir in the mayonnaise mixture until well coated.
