Preheat the oven to Gas mark 5, 190°C, 375°F.
To prepare the rosemary butter; in a small bowl mix all the ingredients together.
Place the joint on a chopping board, make several slits over the surface and season. Spread with the rosemary butter. Put the roasted vegetables in a medium non-stick roasting tin, add the oil and fresh thyme. Position the lamb on top of the vegetables and roast for 35-40 minutes (for medium) on the top shelf of the oven.
Meanwhile, cook the potatoes in a large pan of boiling water for 10-15 minutes and toss in a knob of any remaining herb butter.
Remove the lamb from the oven, transfer to a warm plate, cover with foil and leave to rest for 5-10 minutes. Carve and serve with the gravy, roasted vegetables and potatoes.
1 x 350-400g (12-14oz) lean lamb mini roasting joint (we used lamb thick flank)
Salt and freshly milled black pepper
For the Rosemary Butter:
50g/2oz unsalted butter, softened
30ml/2tbsp freshly chopped rosemary leaves or 10ml/2tsp dried rosemary leaves
For the Roasted Vegetables:
200g/7oz Fluffy potatoes, washed and halved
1 red onion, skinned and cut into wedges
1 sweet pepper, cored, deseeded and cut into chunks
½ small butternut squash, peeled, deseeded and cut into cubes
1 courgette, roughly chopped or sliced
15ml/1tbsp sunflower oil
Few fresh thyme sprigs
Hot gravy, to serve