step 1
Place large baking tray in oven and preheat to 200C/fan 180C/gas 6.
step 2
Peel and dice potatoes into half inch/1cm cubes. Meanwhile melt butter and stir in parsley.
step 3
Heat oil in large frying pan. Over a moderate heat, add cubed potatoes and cook for 5-10 minutes, stirring occasionally to prevent potatoes browning or sticking to the pan.
step 4
Remove rosemary leaves from tough stalks and finely chop. Transfer potatoes to baking tray. Mix parsley butter in with the potatoes and sprinkle with rosemary and season.
step 5
Roast for 30 mins, shaking halfway to prevent sticking.