- Bring a pan of salted water to the boil and blanch the sprouts for 2-3 minutes until just tender. Drain and refresh in cold water. The sprouts can be kept in the water for 4-5 hours if not cooking immediately.
- Heat the oil and butter in a frying pan and add the bacon. Fry for about 3 minutes until golden and crisp, then toss in the chestnuts followed by the drained sprouts. Cook for another few minutes until everything is heated through and golden around the edges.
- Grate over the lemon zest and squeeze in the juice, season with sea salt and freshly ground black pepper and give a final toss together before transferring to a warmed serving dish.
Tips: Halving the sprouts means that the middles soak up more flavour from the bacon in the pan, plus by combining oil and butter for frying, you get the richness of butter without the risk of it burning over the high heat.