Very finely chop the shallots. Roughly crush the mixed peppercorns. Chop the fresh rosemary.
- 1 Heat the oven to 200°C/180°C fan/gas 6.
- 2 Put the lamb in a small roasting tin and drizzle with half the oil.
- 3 Season and roast for 20-25 minutes.
- 4 Remove from the oven and leave to rest for 5 minutes.
- 5 Meanwhile, heat the remaining oil in a frying pan and fry the shallot for 3-4 minutes, until softened.
- 6 Add the brandy to the pan and simmer until the liquid has reduced to about 1 tbsp.
- 7 Add the vinegar and simmer for another minute.
- 8 Stir in the blueberries, sugar, peppercorns and rosemary, and simmer for 1-2 minutes, until you have a rich, glossy sauce.
- 9 Carve the lamb and divide among four warm serving plates.
- 10 Spoon over the sauce and serve with green beans.