Nowhere do folks throw a better party than in Louisiana. I should know – my grandmother Ginny was from there, a town called Plaquemine on Bayou Plaquemine, down which our family hauled Spanish moss, shingles, lumber and oil from a swamp on to the Mississippi. Ginny knew how to party. One of her parties inspired Fellini to make La Dolce Vita. She’s probably still partying now.

To party, you gather all your people together, fill their cups, fill their plates, fill their bellies and let a voodoo magic happen – that spell which falls when inhibitions fade and voices rise. In New Orleans, they call the noise of people enjoying themselves “gumbo ya ya” – many people talking at once, so you can’t pick out the words. That enchanted buzz is the hum of a well-oiled restaurant engine – it makes my hair stand on end when I hear it and makes my heart glow. It is the sound of a happy dining room, the purr of hospitality. It is the first thing I look for when gauging our work at Bocca di Lupo and Plaquemine Lock and the most vital of all the reasons I became a chef.

The phrase “gumbo ya ya” itself derives from the food gumbo; ya ya is just people yakking. Gumbo is the swampy soup that defines Louisiana in a bowl – a concoction of mysterious murk, simple ingredients layered together so their flavours meld, but none is identifiable on its own.

And not just ingredients, but cultures too – Louisiana is a true lady of the night – everyone’s had some input. The word “gumbo” is said to derive either from the West African Bantu word for okra – ki ngombo; or the Choctaw Indian for the herb filé – kombo. French roux forms the base – nearly every Louisiana recipe begins: “first you make a roux” – and further thickening comes either from okra or from powdered sassafras leaf (AKA filé). German-style smoked sausage (with a French name, andouille) spikes many a gumbo pot.

The very origins of this stew are obscured in the depths of its cauldron – it’s likely to be the confluence and evolution of Acadian tricot, French bouillabaisse, Choctaw and African stews. The ingredients came with the colonists, the slaves and the slavers, but the origin of each seems almost immaterial – the voices of each sound as one in the babble of a slowly bubbling gumbo pot.

We have similar shenanigans going on around our Christmas tables at home. Family gather, relax and raise glasses and voices together. We eat turkey and cranberries from the Americas, dates from the Levant, candied fruits from Sicily, red cabbage stewed with apples like the Germans do, and strew together meats and fruits and spices as our medieval forefathers did, and as they still do in the Middle East. We drink wine, sweetened and spiced. And we talk gumbo ya ya.

Turkey gumbo ya ya

This pot of gumbo can easily be increased to make more (excess keeps well, refrigerated or frozen).It will cost 3-4 hours of your life, so have a drink ready. It’s worth it.

The gumbo recipe is a good resting place for any leftovers – Christmas or otherwise. Photograph: Howard Sooley

Serves 8

For the gumbo

Turkey leftovers – carcass, plus around 500g of picked meat (most likely this will be the dark meat, itself a good thing)

5 celery sticks

3 medium onions

3 green peppers

4 garlic cloves, sliced

6 bay leaves

A spoonful of peppercorns

2 jalapeno peppers

Some seafood – 2 dozen raw shell-on prawns (shrimp), or cooked shell-on crayfish (crawfish), or 2 cooked smallish lobsters, or 2 medium (or one massive) cooked crab. Or all the above.

125ml vegetable oil

125g plain flour

400g smoked sausage, chunked (in Louisiana this would be Cajun andouille – use cooking chorizo or smoked Polish sausage instead, or cooked smoked ham hock, or bacon)

100g okra, sliced into 1-2cm rounds

To serve

1 bunch spring onions, thinly sliced

1 soup-bowlful of cooked rice

1 Start the stock – put the turkey carcass in a large pot and barely cover it with cold water. Bring to a simmer and keep it there. Chunk 2 of the celery sticks, 1 of the onions and 1 of the green peppers (seeds, stalks and all) and put them in the pot. Also add 2 sliced garlic cloves, 3 bay leaves, and the peppercorns. Keep simmering.

2 Dice the remaining vegetables for the gumbo – cut the celery and onions into 5mm cubes (throw the trimmings into the stockpot), seed and dice the green peppers and jalapenos the same way (seeds and stalk go into the pot as you go). Keep the stock simmering.

3 Now, shell the seafood. Keep the shells. Keep the brown meat. If using lobster, cut the tail meat into chunks. If using shrimp, remove the veins. Put the shells into the stockpot, and keep it all simmering.

4 Make a roux: in a wide, heavy pot heat the oil and flour together over a medium heat. Stir, sip a beer, and stir again. It will start to turn a nut brown. Keep stirring – but carefully, this stuff is like magma and splashes could be serious. It’s getting darker, but you’re brave – keep stirring until a fine white smoke rises, the flour precisely the colour of melted dark chocolate. Now you have to keep it from burning: quench it with the veg…

5 All at once, add the diced vegetables (celery, onion, green pepper, jalapeno) to the roux along with the garlic and bay. Stir in well with a good pinch of salt – the roux will seize up and darken to the colour of solid dark chocolate.

6 Continue to stir over the heat for 10-15 minutes more, until the vegetables are fully softened and the roux has relaxed to a gloopy sauce.

7 Add the chunked sausage (or ham) and stir it in. Leave it over a low heat while you turn your attention back to the stockpot.

8 Taste your stock. Its been on the heat maybe 2 hours now, and should be delicious. Strain it, and skim off any fat. Measure out 1.2 litres and, in a few fairly rapid additions, stir it into the roux. Keep any excess stock in case the soup needs thinning later. (If you have leftover gravy from a roast, as long as it’s proper stuff, you can dispose of it now by adding it to the pot.)

9 Increase the heat to bring the soup back to a simmer, then reduce it to keep it there again. Add the okra and cook gently for 30 minutes more. The soup should be tending towards a certain thickness and body – not gloopy, but substantial.

10 Remember your turkey meat – the reason you started making this gumbo, now so long ago? Cut it into chunks, small enough to eat in the soup, and add it. Simmer long enough for the meat to start to relax – probably 15 minutes, but this depends on your turkey, and what you did to it this morning .

11 If the soup isn’t for serving now, or you won’t use all of it, chill or freeze anything that isn’t for eating immediately. It can be brought back to a simmer before you add the seafood, which should be just before you eat. Otherwise ...

12 Add the seafood. Simmer for 3 minutes – just long enough to cook the shrimp or warm the crawfish/lobster/crab. Your gumbo is (finally) ready. Serve it in bowls garnished with not too much hot cooked rice and a fair bit of spring onion. It should look like a swamp in a bowl, and taste of the bayou as much as truffles do the earth and oysters do the sea – it is the essence of Louisiana.