Place potatoes in a saucepan. Cover with cold salted water. Bring to the boil over high heat. Boil, partially covered, 20 minutes until just tender. Drain and set aside to cool for 15 minutes.

Preheat oven to 220°C fan forced.

Combine cooled potatoes in a bowl with oil and butter. Tip into a large roasting pan. Use the base of a flat glass to squash the potatoes. Season.

Roast for 35-40 minutes or until golden and crisp. Set aside to cool to room temperature.

For the dressing, combine all the ingredients in a blender or food processor. Blend until well combined. Season with salt and pepper.

Spoon 1 cup of mayonnaise over the base of a large serving platter. Top with a little rocket, then arrange potatoes over greens and dressing. Sprinkle the green shallots and radish on top. Add another layer of potatoes, shallot and radish.

Cut eggs in half then arrange eggs amongst salad. Drizzle with more of the remaining mayonnaise. Serve.