Preheat the oven to 150C/300F/Gas 2.
Roughly chop the new potatoes into quarters, but at odd angles.
Heat a dash of olive oil in an oven dish. Add the potatoes and brown them on the hob over a moderate heat.
Roughly chop the hazelnuts.
Heat the butter in a pan until it is almost going a nutty brown colour.
Pour the butter over the potatoes and mix in the hazelnuts.
Bake in the oven for one hour 30 minutes, or until the potatoes are crisp and golden-brown.