Katie's email went like this: "Hope you're all well and are looking forward to having your favourite nieces in town this weekend. Sorry to be a pain but, due to long-standing digestive disorders (which I won't go into), I've had a test and found out I'm intolerant to dairy, pork and egg white. Not to mention nuts. Although I am happy to eat boiled rice and vegetable broth all weekend, if there is any chance of enjoying your wonderful cooking without the presence of these ingredients, it would be much appreciated."

Wonderful, eh? Who could resist such flattery? But that wasn't quite the end of the bad news, because one of the other nieces informed me that she was off wheat because it had made her arthritis flare up. Arthritis! At the age of 33! What is the world coming to? Altogether it rather hurled down the gauntlet as far as the cooking was concerned. Out had to go many of the usual stand-bys - butter-rich sauces, soufflés, peanut oil, meringues, pork pies, pork sausages, pasta, pizza, puddings with cream or custard. No tarts, toppings or tagliatelle - heavens to Murgatroid, the list was endless.

"Not to worry," I emailed back bravely. "It's not a problem. It's a challenge." What I really felt was that it was a bloody nuisance. I'd have to do some serious thinking for a change, and planning and shopping. In short, the brow furrowed, huffish thought ensued, books were taken down from shelves and studied for inspiration. In fact the whole process became absorbing and, well, enjoyable. It lifted me out of my culinary rut and made me look at cooking from a different perspective. What I found wasn't at all bad, I like to think.

All recipes serve six.

Breast of lamb St Menehould

Saturday lunch. Breast of lamb tends to get overlooked in the rush for luxury cuts, but it has many things to recommend it, not least cheapness. I found this recipe in An Omelette And A Glass Of Wine by Elizabeth David, and adapted it slightly, but in all important respects it is hers.

2 breasts of lamb
1 onion
2 carrots
1 stick celery
1 tsp black peppercorns
2 bayleaves
100g Dijon mustard
6 tbsp breadcrumbs

Preheat the oven to 150C/300F/gas mark 2. Place the meat in a casserole with vegetables, peppercorns and bayleaves, and roast for two and a half to three hours. Lift the breasts out of the liquid and remove the bones (they'll come away easily). Set aside to cool.

About 45 minutes before you want to eat, preheat the oven to 180C/350F/gas mark 4. Spread mustard all over the cooked lamb - how much you put on depends on how much you like mustard - and sprinkle with breadcrumbs. Pop into the oven for 20 minutes to heat through, then slide under the grill until the breadcrumb crust is golden and crunchy. Cut up and serve.

Spiced aubergine

To go with the lamb. Elizabeth David would probably have had a green salad with the meat, and very nice that would be, too, but I wanted something more substantial. I took my inspiration from a fusion (dread word!) of India and Italy.

3 aubergines, washed
4 tbsp vegetable oil (or olive oil)
3 red fresh chillies, finely chopped
2 onions, thinly sliced
1 tsp turmeric
1 tsp ground cumin
1 tsp ground coriander
½ tsp chilli powder
50g fresh ginger, finely diced
2 tbsp unrefined granulated sugar
125ml red-wine vinegar
Salt and pepper

Cut the aubergines into 2cm square chunks, sprinkle generously with salt and leave in a colander to exude liquid for 40 minutes or so. Rinse off the salt under cold water, then pat dry with kitchen towel.

Heat the oil with the chilli in a frying pan and, when almost smoking, add the aubergine. Fry for five minutes or so, turning with a spatula. Add the onions, turn down the heat and fry until softened - about five to eight minutes. Add the dry spices one by one, turning the aubergine and onion mix after each addition to ensure they're well coated. Add the ginger, cook for 10 minutes, then sprinkle over the sugar. Turn up the heat, pour in the vinegar, bring to the boil, then lower the heat until the aubergines are soft but not mushy. Season and serve.

Roast red mullet with braised fennel and pink grapefruit

Saturday supper. Fish, I had decided, but I wasn't sure which fish until I saw Cornish red mullet on the fishmonger's slab. Red mullet has a very distinctive, slightly feral flavour that needs something easy and comforting to go with it. Soft and squidgy fennel is just the job and, by cooking it in stock, you beef up the impact just a touch. The grapefruit cuts through the richness of the dish. If you can't get mullet, use sea bass instead.

4 good-sized fennel bulbs
500ml chicken stock
6 200g red mullet fillets
Olive oil

1 pink grapefruit
Coarse sea salt

Cut the fennel bulbs into 1cm thick slices, place in a pan large enough to hold them in a single layer (you may have to do this in batches), then cover with stock - if 500ml isn't enough, just use more. Bring to the boil, turn down the heat and simmer, uncovered, for about 45 minutes, until the fennel is very soft and most of the stock has evaporated.

Peel a pink grapefruit, removing all the pith. Over a bowl (to catch the juice), cut out each segment by slicing inside the membrane on each side, slicing in towards the centre. Cut each naked segment into six or eight pieces.

Turn the oven to maximum. Place the fish fillets on an oiled roasting tray, dribble a little olive oil over the top and sprinkle with a little sea salt. Slide into the oven when it is at its hottest, and roast for four to six minutes, until cooked through.

To serve, add any pink grapefruit juices to the reduced chicken stock; plonk a fish fillet on top of a pile of fennel, splash the juices around the plate and scatter the grapefruit bits all over.

Braised pineapple with ginger and vanilla

Sunday lunch, after rabbit stew. I am still working on the recipe, and will come back to it when I am happy. Of course, the pineapple would have been even better with cream or ice cream, but we showed solidarity with Katie all the way down the line.

1 ripe pineapple
1 vanilla pod
50g fresh ginger
115ml ginger wine (Crabbie's or Stones)

Peel the pineapple and cut down the length of the fruit into slices, so that you have six long, fattish portions. Peel the ginger and cut into matchsticks. Stick the ginger matchsticks into the slices of pineapple, four to six sticks per slice.

Cut the vanilla pod down the middle. Put the vanilla pod into a large frying pan. Lay the slices of pineapple flat in the pan. You may need to do this in batches. Pour the ginger wine over the pineapple, place over a low heat and cook until the pineapple is soft. Serve hot or warm with the cooking juices poured over them