Chop a couple of red onions into chunky segments and place in foil.
Cut lamb neck fillet into cubes around 2.5cm. Slice garlic and push into a little cut into each lamb cube and place in the foil.
Add fresh rosemary to the dish and squeeze over the juice of 2 lemons and close up the foil to make a secure parcel.
Put in the oven for 3 hours.
Serve with cauliflower couscous with feta, pinenuts, leeks, courgette and olives. Or a simple salad.