In Mayfair’s white-tablecloth restaurant scene, Lucknow 49 stands out for all of the right reasons. Cheerfully decorated with hanging garlands and vibrant textiles, this colourful new Indian restaurant on Maddox Street specialises in slow-cooked Awadhi cuisine from Lucknow in northern India, and the surrounding region of Uttar Prades – a fragrant cuisine that has historically been overlooked in London.

It is the first of its kind in Europe and the latest offering from Dhruv Mittal, founder of Dum Biryani in Soho. “I first discovered Awadhi cuisine when I was working at The Oberoi Amarvilas hotel in Agra,” recalls the affable Mittal, who trained under Heston Blumenthal. “The food was unlike anything I had ever tasted before. Everything is slow-cooked, well perfumed and incredibly balanced, which was a refreshing way to view Indian food.”

The menu at Lucknow 49 kicks off with tender, melt-in-the-mouth beef patties (Galawat kebabs), which are a lunchtime specialty in Lucknow, originally invented for a toothless Lucknavi king to curb his kebab cravings. Next, lentil-stuffed flatbread parcels are perfectly formed, in a creamy pool of zingy yoghurt with tamarind and coriander chutney.

A lamb leg is steeped in more than 30 spices and cooked in slow-bubbled trotter stock for twelve hours to reach a glutinous, rich and tender consistency, mopped up with Gilafi Kulcha – a layered, puffed-up bread. Also on the menu is fragrant aloo gobi; creamy dal (slow-cooked in milk for six hours) and Mittal’s signature selection of biryanis, serving spicy goat meat or green beans with saffron-infused rice.

It’s like a big, informal dinner at your friend’s house – if your friend had a chic green marble dining table and a penchant for throwback nineties slow jams. Cushions are made from typical Lucknavi sari fabrics, while photographs of Indian generals, guards and past Lucknavi kings hang on the walls. “The restaurant was designed to resemble the warmth and comforts of a Lucknavi home. We want the atmosphere to feel intimate yet casual and accessible.”

At Lucknow 49, cooking is slow but service is quick-sharp. This is an unpretentious restaurant in Mayfair where customers leave full to bursting – and for great value. Don’t overlook the cocktail menu, which is the perfect foil to Mittal’s spice and flavour. Highlights include a palette-cleansing, foamy pisco rose sour and the house negroni, made using an artichoke liqueur.

There is only one dessert: a confident clay cup of fragrant cardamom-infused aminabad kulfi (Indian ice-cream), nuanced with saffron and swirling with almonds. “We serve the kulfi in a clay cup because it’s authentic to its region and the cup is said to increase the nutritional value and taste. I like simple menus, where there is a limited choice but everything is done well and kept as authentic as possible.”