Preheat the oven to 400 degrees F.
Cut any larger potatoes in half so they are all roughly the same size. Put into a saucepan and cover with cold water. Bring to the boil and gently simmer until fork tender, 10 to 12 minutes. Drain well using a colander.
Tip the potatoes out onto a baking sheet and press each one down in the middle with a potato masher or your thumb to crush it. (Let cool slightly before crushing if using your thumb.)
Drizzle the olive oil over and sprinkle with a couple pinches of salt and pepper. Gently toss each potato in the seasoning.
Bake the potatoes, flipping them halfway through, until crispy and golden, 35 to 40 minutes. Serve with the Lemon Dill Mayo.
Add the mayonnaise, dill, lemon juice and a pinch of salt to a medium bowl. Mix well to combine.