Cauliflower au gratin

• 1 large cauliflower
• 1 onion
• 6 bacon rashers
• 2½

Trim the cauliflower and break into medium-sized florets. Add to a pan of boiling salted water and cook until just tender – about 8 minutes – then drain. Reserve sufficient cooking water for the sauce and arrange the cauliflower florets in a buttered serving dish. Peel and chop the onion and trim and chop the bacon rashers. Melt ½