Menuwatch: Kindle, Cardiff

We went through a great debate on every single detail of the restaurant

The basis for each of the small plates in the 76-cover restaurant is the open wood fire chef Tom Powell and his team cook on. "I try to incorporate fire into everything we do, whether it's direct cooking or slow cooking overnight," he says. Powell also has a smoke box hung up on the fire rig which he uses to inject flavour into dishes such as roasted cauliflower, pickled cucumber and peanuts, which is initially cooked in the kitchen's standard combi oven before being finished in the smoke box.

Fire is ever-present. An amuse bouche of fried mushroom is sprinkled with onion salt made in-house by blitzing the burnt skins of onions and shallots used elsewhere on the menu with salt. The onion salt is also used in a dish of flatbread with burnt spring onion butter, inspired by Iranian sangak bread, meaning ‘small stones'. It is cooked on a bed of hot pebbles Powell "borrowed from a local beach" to create the spotted pattern. For the charcoal-coloured butter Powell "absolutely destroys [spring onions] over a direct fire" and makes a purée, which is beaten with the onion salt into soft butter.

Powell, who previously worked as head chef at the Michelin-starred Walnut Tree in Abergavenny, works with the restaurant's suppliers to get hold of produce at its seasonal peak. He lets ideas for new dishes come naturally and changes the menu by around four dishes a month, so it slowly rotates.

Meat doesn't feature heavily in Kindle's menus, and when it does Powell doesn't go for the typical cuts, instead opting for lamb breast, offal , which he serves in an empanada, or hanger steak. The latter sees the meat marinaded in olive oil, roasted garlic, thyme and black pepper, and then cooked directly over the flame before being sliced. It is accompanied by salsify, which is also roasted on the fire, sliced into batons and seasoned with caraway salt, which Powell makes by blitzing toasted caraway seeds, sugar and salt. The salsify is reheated in the smoke oven and served with the steak and a cream of mushroom sauce, made from roasted Portobello mushroom purée.

The environmental ethos of Kindle doesn't end with the food. "We went through a great debate on every single detail of the restaurant," Phill explains. Ultimately, the decision was made to only provide guests with napkins when requested, after viewing the environmental impact of disposable napkins versus cloth, which would need to be laundered even if they sit untouched on the table.

"How often do you sit at your dining table and whip out a napkin before you eat at home?" asks Lewis. Outdoor heaters were dismissed too: "We can't think of anything less sustainable than heating the outdoors."

The Kindle team took great care to restore the grounds around the building, installing raised beds for herbs and vegetables made from the scaffolding from the building work. As space is limited, they don't rely on what they grow to support the menu, but rather for helpful additions down the line, for example interesting garnishes or chillies from the greenhouse, and anything that needs to be used up will make an appearance. When they were preparing to open last summer, Swiss chard was planted in the Hobbit-esque garden and it flourished. "It was bloody everywhere," says Powell, who created a dish of pig's head meat wrapped in Swiss chard to make the most of it.

With sunnier days ahead, the team are looking forward to a boom in bookings. Once enough cash has been generated, the couple plan to once more renovate the restaurant to allow for indoor seating. The materials used in the original build were designed so that they will fit in the next build, with as little waste as possible. "It's a real asset to Cardiff I think, from a derelict building to what we've created," says Phill. "People stop and take pictures of the garden; it's a really beautiful setting."

From the menu

• Flatbread with cultured butter £4.50
• Purple sprouting broccoli with XO sauce or salsa roja £7.50/£6.50
• Baked potato with roasted garlic aioli £6
• Leek katsu £8
• Cheese and potato pie £8
• Deep-fried goats' cheese with cauliflower £7.50
• Mackerel pretzel baguette with pickled kohlrabi £8
• Stone bass and scallop bouride £14
• Rhubarb and custard cannoli £7
• Baked white chocolate, ice-cream sandwich £8

Sophia Gardens, Cardiff CF11 9SZ

www.kindlecardiff.co.uk