Make cuts across the width of each potato, 1 to 2mm apart, all the way along. Slice about two-thirds of the way into the flesh.
Pick the rosemary, then stuff the cuts in the potatoes sporadically with the rosemary leaves.
Cube, then dot the butter over the base of a large roasting tray and drizzle in the oil. Pop the tray into the oven for a few minutes so that the butter melts, then place the potatoes carefully into the tray.
Roast for 50 to 60 minutes, or until the potatoes are golden and cooked through, basting with the butter in the tray a few times during cooking and turning regularly until they are golden and crisp all over.
Drizzle all the spuds lightly with the honey, then return to the oven or another 5 minutes.
Remove from the oven and place the potatoes on a board or platter. Crumble over the gorgonzola and serve while still warm.