Preheat an oven to 190*
Season the lamb rumps with the salt and pepper.
If the cap of fat is very thick, score with the tip of a knife.
In a hot pan, lightly oil and sprinkle across the rosemary sprigs, then place the rumps skin side down until golden brown.
Turn, until all sides are coloured.
Return to the skin side and cook in the oven for approximately 8-9 minutes.
The flesh when squeezed from the sides should have a spongey but firm texture.
Take out of the oven and turn the rumps to the opposite side to allow to rest.
Remove the leaves and finely slice the caulifower head.
Add to a thick based pot with the milk and salt and white pepper .
Bring to the boil and then cook covered for approximately 15 minutes on a gentle simmer until the cauliflower is soft.
Remove the cauliflower and puree on high speed, adding the liquid as necessary to obtain a smooth silky 'custard-like' texture.
Separate the cloves of garlic but leave in their skins, place in a tinfoil parcel along with the olive oil and seasoning and bake in the oven on a tray until soft. (Around 20 minutes)
Remove from the shells carefully and slice each clove into 2.
Bring a large pot of water to the boil.
Strip the Cavolo Nero leaves from the stem and cut into roughly 5 pieces each.
Cook the cavolo nero for approximately 3 minutes in the boiling water, then remove and chill rapidly in cold water.
Lightly crush the hazelnuts with the side of a knife.
Toast on the tray with the garlic for 10 minutes.
Pick the remaining rosemary and finely slice.
Juice the half lemon.
In a saucepan, cook the butter to a nut brown stage,add the rosemary, roast garlic and hazelnuts, swirl the pan to infuse and finish with the lemon juice and any juices that have seeped out of the rested lamb.
If necessary, warm the puree in a small sauce pan.
Warm the lamb rumps back up in the oven with the cavolo nero for about 2 minutes.
Serve the puree spread across the plate with the lamb sliced on top af a heap of the cavolo nero.
Spoon the buerre noisette on top and around the plate.
«Add a little reduced veal or lamb stock (jus) to the buerre noisette to further enrich it.»