met Ruth Rendell in 1986 when she was fifty-six and I was twenty-seven. We were friends until her death in 2015, when she was eighty-five and I was fifty-six.

I met her when she was at the age I am now – and that changes the way I think about our friendship, and her remarkable kindness to me.

I had published just one book back then – Oranges Are Not The Only Fruit. She was a celebrated international success. The Queen of Crime.

We met because she needed someone to house-sit while she went on a book tour of Australia for six weeks. I was writing my second novel, The Passion.

With her characteristic thoughtfulness for young writers, Ruth said that she too was writing her second novel – as Barbara Vine, the pen-name she had recently assumed for thrillers of terrifying psychological insight.

Ruth and I really liked each other. In some ways it was as simple as that. Over the years we started our own tradition of spending Christmas Day or Boxing Day together. Her son lives in America, and after her husband, Don, died, our Christmas times became more important to us both.

The routine was always the same. She told me when to arrive so that we could go for a long walk around London. She planned the route – there was always something she wanted to see. Her later work is full of London. She loved walking in London and Christmas Day is quiet.

After the walk, we’d eat. Ruth cooked. She was a nimble cook, no fuss. She wasn’t all that interested in food, but she liked making Christmas dinner.

What did we have? Pheasant, roast potatoes, carrots, a green vegetable of some sort, usually whatever I had grown in the garden that had survived slugs and pigeons. So we might eat sprouts if we were lucky, kale if we weren’t. Lots of gravy and, and this is the point of the story, Ruth Rendell’s pickled red cabbage.

Ruth made the pickled cabbage in early autumn. She always rang me to tell me the day. ‘Oh, Jeanette, it’s Ruth; I’m pickling the cabbage and then I’ll walk down to the House.’

She meant the House of Lords, where she was a Labour Peer.

It’s not generally known that Ruth was a big Country and Western fan, so the cabbage-pickling was accompanied by ­Tammy Wynette or k. d. lang.

I was never present at the process of pickling. Ruth was her own alchemist and, whatever she did, she did it better than me. I have her recipe but not her knack. Pickling was something that Ruth’s generation of women understood. Ruth was born in 1930. As a teenager in the Second World War she was pickling for victory. And her own mother was Swedish, so, if you think about it, Ruth’s pickling skills go back to the turn of the century, and were learned from a tradition whose winter food-supply depended on salting and fermenting.

And of course when Ruth was growing up in London, first there was the Depression, then came the war, then rationing – and nobody had a fridge.

When her husband was alive she pickled him gherkins. He loved a gherkin. She told me she had pickled rabbits during the war.

‘What did they taste like?’

‘How should I know? It looked disgusting. I wasn’t going to eat it, Jeanette!’ And then that laugh. Ruth had a wonderful laugh, directed at the comedy of life, its absurdity.

It’s fair to say she was a connoisseur of the pickle. She loved a pickled herring. I adore pickled cucumber and I always order it when I eat at the Wolseley Restaurant on Piccadilly in London.

Ruth liked me to take her there. Generally in life Ruth found herself paying the bill; she was both wealthy and generous, so it was good for her to be taken out, and our rule was that she never paid at the Wolseley. I always got there first so that I could order champagne without having a fight . . .

I find that champagne and pickled cucumber is an excellent combination. Ruth, though, never thought much of the Wolseley cucumber.

‘Mine’s much better, you know . . . ’

And it was.

Ruth owned a set of ancient pickling jars with rubber seals and screw-top lids. When filled to the brim these were left to sit in the back of the larder like a question no one can answer yet.

Opening the jar was a moment of anticipation and anxiety. Fermentation is fraught. You might make something exquisite – or something that stinks.

It never went wrong – but until you open the jar you really don’t know.

The colour of pickled red cabbage is exquisite, and the perfect red for a Christmas feast. Ruth served hers in a pale green bowl. The sharpness of the taste is a great counterpoint to the richness of Christmas dinner.

Apart from the vegetables, all I had to do was bring the wine. Ruth’s wine knowledge was zero and left to herself a drink would be a supermarket bottle of wine-lake Chardonnay. But she loved champagne, so that’s what I brought her. Veuve Clicquot.

After our meal it was TV time. Ruth was in charge of what we watched, but it had to be something scheduled in real time – no DVDs, no catch-up TV.

Ruth put her feet up on the sofa with her beloved cat, Archie. I’d lie on the other sofa, and we’d complain about the telly. It was important to be able to complain about the telly.

About ten o’clock, Ruth would zap the zapper and say, ‘I can’t stand any more of this rubbish, can you.’ (It was not a question.) Then she followed it with a second non-question: ‘Shall we have the Christmas pudding.’

The pudding – always made by a friend of hers in the House of Lords – was the size of a cannon ball and just as heavy. It was a lethal weapon disguised as dessert. Ruth let it boil for hours wrapped in a rag in a double pan – the old-fashioned way. As her kitchen ventilation wasn’t that great, we spent the later part of the evening in a Hitchcock steam that smelled of washing. Even the cat coughed.

When the pudding was thought to be ready – and Ruth, the most precise of persons, never used a timer – she set about making ­custard. While this was happening she’d sing a bit – usually Country and Western, or sometimes Handel; she was a big Handel fan. Sometimes it was ‘Jolene’ medley’d with hits from the Messiah.

The custard was proper home-made with milk and eggs. The ­effort had to be encouraged by opening a further bottle of champagne – but only a half.

Then the pudding was tipped onto its dish, covered in brandy by me, and set alight by Ruth. Ruth always said she was too full to eat any, and then munched her way through exactly one half.

The next day she’d send me home with the rest of the jar of red cabbage.

The last Christmas I spent with her was 2014. Ruth Rendell had a stroke on January 7th 2015 and never recovered.

I miss our Christmases together. And the red cabbage.

Here’s her recipe.

YOU NEED

Organic red cabbage – not too old or tough. Use a big one or two small ones.

Pickling vinegar. More on this below.

100 g sugar. Not all recipes use sugar but Ruth’s does.

150 g good-quality coarse sea salt. The salt depends on how much cabbage you are making. The point of the salt is to draw the water from the cabbage leaves.

About the pickling vinegar: you can buy this from the shops but Ruth made her own and kept some to hand in the cupboard in case she ­wanted to make a Cheat’s Red Cabbage (instant pickled effect). The pickling vinegar lasts ages if you keep it in a good airtight bottle and decant it into smaller bottles as the volume goes down. Here’s how you make it:

Put 2 pints (just over a litre) of malt vinegar in a big pan along with 6 fresh bay leaves, a couple of teaspoons of peppercorns, some caraway or coriander seeds if you have them, mustard seeds as well, or instead (I said this was a personal recipe!), a few cloves. Whatever. For Ruth it really was a whatever, because she knew what would work.

Bring to the boil. Let it cool down somewhere that won’t stink out the place with vinegar. I cover mine and put it outside overnight.

Leave all your spices in the vinegar mixture until the next day then sieve the vinegar clear. Some people start the process by putting all the spice-junk in a spice bag and throw the bag away afterwards but Ruth thought that was a faff. ‘What’s wrong with a sieve.’ (Another not-a-question.)

METHOD

Get rid of any old outer leaves. You are eating this stuff later.

Fine-chop the red cabbage into forkful-sized shreds. Put these into a big bowl and work the salt through the cabbage. Cover and keep in the fridge overnight.

The next day bring your pickling vinegar to the boil again, let it cool off and add the sugar, stirring well. If you put in the sugar when the mixture is too hot you will get a kind of vinegar syrup like something from a disastrous chemistry lesson. Not good.

Rinse the salt off your cabbage and dry it well.

Line up your airtight jars, which have been sterilised, if used previously, and which are perfectly dry and clean. We all have to die but not of cabbage poisoning.

Fill each jar a third full of your pickling liquid, then pack the jars tight with cabbage. And I mean TIGHT! Then fill the jars to the very brim with the pickling vinegar. No air pockets!

Seal the jars, wipe any spills and store your pristine pickled cabbage in a dark, brooding place till needed.

The problem with the recipe is that Ruth was a virtuoso pickler, so if she wanted to add some red wine to her pickling mixture, or use cider vinegar, she did that. Similarly, she sometimes chopped some windfall apples in with the red cabbage. Or a little bit of onion. (I know, I KNOW.)

She just couldn’t get it wrong. Unlike me.

Remember old Sam Beckett? ‘Try Again. Fail again. Fail better.’

Happy Christmas, Ruth.