To celebrate the launch of their latest cookbook, Ella Walker spends a day in the kitchen with married chefs Katie and Giancarlo Caldesi.

When I arrive for my Tuscan masterclass, Giancarlo Caldesi is whisking custard in a stainless-steel pan. He motions me over to sniff it, fragrant with saffron, before explaining - in great detail - the art of using cling film to seal in the warmth of the custard and avoid it growing a thick, school dinner-style skin. The man is all about detail, and all about cooking with emotion.

The Tuscan-born chef and his wife Katie, a cookery writer and former artist - who is stirring a bowl of ricotta and icing sugar, puffs of it dancing off the spoon - met in 1997. Two decades on, they have two sons, two restaurants, La Cucina Caldesi and Caffe Caldesi, and their own Italian cookery school.

But today, they are buzzing around their slick teaching kitchen, showing me how to make a whole menu's worth of dishes from their latest cookbook, Tuscany. It is their fifth book in a series that each take one Italian region as their focus; they've already covered the Amalfi Coast, Venice, Rome and Sicily.

Homegrown vegetables are key in traditional Tuscan cuisine Giancarlo was born and raised in Montepulciano Stazione, near the Umbrian border Katie explains, while her husband shows me (repeatedly) how to scoop the egg white-rich batter of a batch of Sienese almond biscuits into quenelles using two spoons, breaking off every now and again to scold me for being too rough with them ("You must be gentle," he cries).

"They only ate organic, seasonal, fresh, homegrown food," Katie says, describing her husband's childhood. "Giancarlo's mother would cook in a cauldron over a fire - we still have it, we serve pasta in it at parties - and then the outdoor oven for baking would only be fuelled every 10-14 days, and the whole village would come and help." It sounds idyllic, but it was a way of living dictated by poverty, combined with the tradition of eating what you've grown yourself.

Don't be afraid to combine savoury with sweet Later, the marshmallowy-soft almond biscuits eaten and duly dunked in a creamy mixture of coffee, ricotta and brandy, Katie gets me started on a sweet Swiss chard tart - yes, a greens stuffed dessert. "It's a traditional recipe from Lucca," she says, explaining how post-war poverty led to people bulking out dishes, savoury and sweet, with vegetables that were more readily available.

Using our hands, we squash mounds of cooked chard, ricotta, pine nuts, cinnamon, walnuts and raisins into a pastry case, while trying not to be distracted by Giancarlo making his favourite Caffe Caldesi tomato pasta sauce nearby.

The couple are hilariously distracting, telling snippets of stories, talking over one another, bickering, wheedling and mocking each other constantly. At one point, Giancarlo proclaims: "I'm beautiful, I'm sexy and clever and very, very modest," to which Katie responds by continuing to stir a pan of lentils while wryly rolling her eyes.

Italian cooking takes time, patience and care Giancarlo takes his food seriously though. Hence why he keeps interrupting our tart-making to charge me with tasting his slow cooked tomato sauce at every stage of its development. He tells me: "In Italy there is a feeling to the food - you can tell if an Italian chef made it or not."

Taking the right amount of time over food - whether it's a joint of meat or a simple pasta sauce - is important too he explains, and rushing is not the done thing in Italy. "We spent a whole day making a wood pigeon Ravioli," Giancarlo says with a bemused huff, remembering their Tuscan tour for the book. "So long! You cannot be English in Italy, you must go with the flow.

"If you can't embrace the culture," he adds thoughtfully, "you can't embrace the food."

Katie and Giancarlo pack me off with boxes of Swiss chard tart (you'd have no idea you were getting your daily dose of iron eating this, especially when topped with a dollop of that saffron custard), luxurious lentils infused with homemade stock and the leftover almond biscuits, downy with icing sugar. It would be pretty tough to not embrace food like this.

  • Tuscany: Simple Meals And Fabulous Feasts From Italy by Katie and Giancarlo Caldesi is published by Hardie Grant Books, priced £36. Available now.