Brush the lamb with olive oil and rub with garlic, rosemary and pepper. Place on a baking tray lined with baking paper and place in oven for 20-25 minutes for each 500g.
Peel the sweet potatoes and cut into squares. Cook them in boiling water for 15-20 minutes until tender.
Mash sweet potato with milk until smooth. Add almonds and spring onions.
Cook green beans in boiling water for 1 minute.
Slice lamb and serve with sweet potato mash and green beans.
To test how well your roast is cooked try pressing the outside centre of the meat lightly with tongs. If it feels soft and springy it’s in the medium-rare range. If it feels slightly firm and springy it’s medium. Any firmer to touch and its on its way to well done.