Angela Hartnett's Spring Lamb With Charlotte Potatoes and Broccoli Recipe

The weather may not be playing ball but get into the spirit of spring anyway with this fabulously tasty dish.
Believe it or not, spring is here and the new-season lamb is coming through. This tasty and quick dish really makes the most of its fabulous flavour.300g charlotte potatoes, skins on, scrubbed
250g sprouting broccoli, roots trimmed
2 tsp vegetable oil
4 lamb rumps, trimmed, fat scored
50g butter
Clove of garlic, crushed
Sprig of rosemary
2 spring onions, chopped
A few mint leavesFor the dressing:
75ml olive oil
15ml red wine vinegar
1 tsp of dijon mustardPut the potatoes into a large pan of cold water, season, bring to the boil, and then simmer for 20 minutes until cooked.Drain the potatoes, reserve the water, add the broccoli and cook for five minutes before refreshing in cold water.Meanwhile add the vegetable oil to a warm pan, season the lamb and brown off.Melt the butter, and when it starts to colour, add the garlic and rosemary and baste the rumps for 6-10 minutes, depending on how well you would like the lamb cooked.Remove the lamb from the pan and allow to rest for a few minutes.Beat the oil, mustard and vinegar together until emulsified.Halve the potatoes and toss with the broccoli, spring onions and mint.Slice the lamb and lay on top, check seasoning and serve.• Angela Hartnett is chef patron at Murano restaurant and consults at the Whitechapel Gallery and Dining Room, London. Twitter.com/angelahartnett
Lamb rump, charlotte potatoes and broccoli. Photograph: Graeme Robertson for the Guardian