"Another year, another culturally-confused holiday for my family" commented Anbara on her post on twitter. Image Credit: Supplied from Social Media

It was a glorious July afternoon and my Arab grandmother - Teta, we called her - was being daubed liberally with margarine by my Scottish grandmother.

On a goofy impulse, Teta had climbed inside an inflatable rubber ring and become stuck. We all took turns trying to budge it, but she was lodged firmly.

So, Granny retrieved a tub of marge. My grandmothers wept with laughter as Granny smeared Teta with grease until the ring popped off like a champagne cork. We all cheered.

Teta decided not to go swimming after all.

When my parents met in the 1980s, they were newly arrived in England.

My father was a posh international graduate student from Beirut and my mother was a working-class Scottish girl doing night shifts in the local pub while working as a librarian.

They were married in a civil and a Muslim service, where my grandparents exchanged gifts to symbolise the union of our families: a kilt and a jellaba.

My siblings and I grew up in London and negotiated our divided identity with no small amount of confusion and crisis. Our grandparents represented the extreme split in our heritage.

We spent a summer under Israeli bombardment in Beirut with my Arab grandparents; we spent winter evenings tucked up next to a gas fire eating mince and tatties with my Scottish grandparents. I had rarely seen my grandmothers in the same room until one year we decided to take a joint family holiday in Cornwall. I was 10.

My grandmothers were my heroes in different ways.

A chain-smoking maverick in a pinafore, Granny was from a small mining village in the middle of Scotland. She was a snooker connoisseur with a lusty baritone and a love of grisly police procedurals. Tirelessly productive, she crocheted blankets at a rate of one a day. Granny believed in fortification against discomfort; she was a consummate master of the cosy. On cold evenings, she would warm our beds with an electric blanket and a hot-water bottle, then tuck us in so tightly that we lay bound to the bed, sweating and gasping for breath.

My other grandmother is the most eccentric person I have met. Irreverent and misleadingly ditzy, she gleefully stole from hotels, trespassed for wild flowers and drove like a Beiruti speed racer. Teta was from a privileged background: she had grown up in a mansion and was the sister of a Lebanese prime minister. She was well educated and sophisticated. She had an ear for classical music, spoke three languages fluently and performed calculations in French. She was a friend of Kim Philby and Patricia Highsmith, but, if you asked her questions about the glamorous people she had met, she would produce breathless and giggly anecdotes about their pets.

The summer we arranged the joint holiday, I counted down the days until I would be cosseted by so much grandmotherly attention. But, in the weeks leading up to the trip, I began to worry. Granny did not like to go swimming or go on walks. Granny went to church; Teta cackled at the idea of mosque. Granny cooked; Teta had a cook.

In the narcissistic preoccupation of identity politics, my siblings and I assessed each other against a roving scale of categorisations: were we like Granny - pragmatic, stoic, competent? Or were we fussy, flamboyant and impulsive, like Teta?

The summer began and we piled into a huge rented house. Granny was palpably nervous - she did not know how to be lazy. I had seen photos of my mother's childhood holidays, with Granny wrapped in a blanket and a woollen hat on a grey pebbled beach. It was probably August. But now that we had secured a summer vacation with nothing for her to do, or fix, or crochet, Granny could not sit still. "It'll just take a minute," was her perpetual refrain as she leapt to her feet to adjust cushions or make cups of tea.

Teta was the youngest of 12; she had grown up with an army of sibling caretakers, while Granny had been a lifelong caregiver. Teta was enthusiastic about the luxury of leisure time. Each evening, she counted down to the curfew of a permissible whisky, while Granny perched on the edge of her seat, unable to give herself permission to relax.

Over pots of boiling stock, my grandmothers shared jokes and stories, poking fun at us, at themselves.

One Saturday, I dragged them on an expedition to the tiny, slanted high street. I had an ulterior motive for the outing: a lurid confection I had spied in the window of a sweet shop. Vivid pink with a stripe of white through the middle, it conjured the Enid Blyton magic of a bucolic childhood I never experienced, as I grew up in the middle of London.

I fantasised about this treat for days - I was delirious for it. When the afternoon arrived for a special outing to the shop, I was half-crazed with anticipation. After my first mouthful, however, I broke into grief-stricken tears. It was coconut-flavoured. I sobbed. The pink and white stripes did not taste different at all. I was devastated. A betrayal! My grandmothers locked eyes. "Don't waste it," they said in unison.

While food waste hardly seems a foundation for a friendship, it was the first time I had seen them agree wholeheartedly. Their parsimony about food immediately became a point of solidarity. Teta would cut around putrid sores in fruit and then nibble them up: "Mmm," she would say, "delicious."

Granny sawed the burnt crusts off my toast and then crunched them herself. That summer, Teta and Granny commandeered the kitchen. The meals were delicious, but the leftovers were a plague.

During each meal, they were dutifully returned to the Tupperware, the same plate of rice and peas hardened into a glistening shell. Dingy rags of chicken skin sat in saucers of stiff dripping. Table crumbs were scattered on the lawn for the birds. At restaurants, Teta would fold tiny scraps into her napkin and hide them in her handbag, bringing them out again at home with a flourish. "Look," she would cry, "liver!"

Over pots of boiling stock, my grandmothers shared jokes and stories, poking fun at us, at themselves.

Despite their differences, they shared histories of personal struggles. Two of Teta's houses and their entire contents had been bombed and occupied. Granny had worked her entire life, securing her financial independence through difficult jobs: at a petrol station; at a hospital, where she washed and prepared bodies after death. Teta was a breast cancer survivor. But their tragedies were discussed with a shared insouciant challenge to authority, an irreverent form of defiant resilience. Granny's osteoarthritis pained her every move, but good luck to anyone who suggested she sit down and relax. With cheerful enthusiasm, Teta encouraged us to play catch with her prosthetic breast.

At the time, I had been afraid that my grandmothers' differences were an omen of something incongruent about me and my siblings. While I know as an adult that mixed-race families are not a magic solution to racism, as a child their friendship seemed to validate our bothness.

One Sunday, when Granny made pancakes still lemony from washing-up liquid left in the pan, she and Teta sat down and ate the whole pile together. Watching them scoff and laugh and gobble up inedible pancakes acted as reassurance for my childish anxieties that it was possible to be Scottish and Arab, Presbyterian and Muslim; that we could navigate the contradictions through squabbling, forgiving, loving and Tupperware.

My grandmothers died within months of each other in 2004. In a total coincidence, Teta was buried next to a gravestone sharing Granny's name. I think of their friendship whenever I scoop a froth of mould from the top of jam or boil up carrot shavings for stock. And I am still surprised that they agreed to waste the margarine.

Written by Anbara Salam, author of 'Things Bright And Beautiful'