Stop press! Olive oil is a culinary super-power. Here’s what I look for in a bottle

Extra-virgin olive oil is something I think about a lot. Above all, how much we have left in the bottle-on-the-go and if we have any more in the cupboard. Because extra-virgin olive oil (and from now on I am going to type the rather annoying acronym evoo) is one of the most important ingredients in the kitchen – not simply liquid fat, but flavour and deep seasoning, with the ability to act like herbs and spices, not to mention the antioxidants and 20 types of polyphenols and anti-inflammatory properties. Which is why, although evoo is ideal for cooking, it is a substance to be enjoyed on salad or zigzagged over warm vegetables.

I also think about the wildly different flavours and the wildly different price tags attached to each bottle. And it is those vast differences that keep me open-minded about evoo, and restless: forever trying different brands and, whenever possible, meeting different makers in different countries. I may cook ostensibly “Italian” food, but most of my dishes could come from another place, too, which is why the evoo in the kitchen could just as easily be Greek, Spanish, Palestinian, Lebanese, French or Croatian – all of which I find compatible with my cooking.

Just to recap, evoo is the liquid fat obtained by pressing olives, which are fruits. The best evoo generally comes from half-ripe (greener) olives, which, given that they are firmer, produce less oil; very ripe, black olives produce more oil of lesser quality. Once picked, olives need to be processed as soon as possible – that is, crushed, then centrifugally spun to separate the pulp, water and oil, all in scrupulously clean machinery and at a steady temperature, which preserves the natural aromas of the olives: tomato vines, almonds, artichokes, pear drops, basil, black pepper to name just a few. Good makers get the olive to the press in hours, while others might leave them to sit in crates for weeks – and remember, they are fruit like any other, which is why those less pleasant odours might creep in and why less scrupulous producers might start adding chemical smells or green colouring.

It takes about eight kilos of olives to make a litre of oil, which, to be considered evoo, needs to have no defects and no more than 0.8% of free fatty acids. And that comes at a price: expect to pay between £14 and £30 a litre, which is expensive to extremely expensive, I know, which is I why I have to remind myself what an important ingredient it is, how much work went into making it, how delicious it can be, how a few tablespoons go a long way, in pasta, for braising chicken or in a cake batter.

Nature’s candy | For the last few years, I’ve candied citrus peel following online tutorials and recipes: the results, although fun, didn’t reflect the effort or stickiness involved. I really like candied fruit, though, so this year I used Camilla Wynne’s recipe for candied mandarins from her magical but practical new book Nature’s Candy, and Kitty Travers’ method for candied lemon from her ice-cream book La Grotta Ices. Both recipes take at least a week, but only require about five minutes a day, and the results are sticky and stunning. Also, they’re the most delicious candied peel I have ever eaten!

What I watched | In Iranian director Mohammad Rasoulof’s extraordinary film The Seed of the Sacred Fig Tree, family meals and the calm domestic rituals of laying out clothes and food contrast the growing tension between Iman, a lawyer recently promoted to state investigator, his wife Najmeh, and their two teenage daughters. Everyone in the family is anguished in different ways by the civil unrest and anti-hijab protests all over the country; a domestic tale twists into something entirely different.

The best thing I ate | Saba isconcentrated grape syrup and typical in central Italian wine-producing regions. It is gorgeous stuff that tastes, unsurprisingly, like very reduced red grape juice, with a touch of balsamic vinegar and treacle. It’s brilliant on baked vegetables, in a dressing for salads, or poured over ice-cream. If you can’t find it, you can make your own saba-ish by reducing a bottle of red grape juice to one-third of its original volume and keep it in a sealed bottle or jar in the fridge.