The restaurant, run by MasterChef finalist Matt Healy, took first place in the Unilever competition, which celebrates the venues which serve the best version of the popular national dish.
Commenting on the win, owner and head chef, Healy said: "We're so chuffed to have beaten some incredible restaurants from across Britain to take home the title of Best Roast Dinner.
"One of our roast dinners have proved such a hit that we get booked up weeks in advance, and we've had such positive feedback from diners.
"It's great that the judges agree and think our offering is the very best that Britain has to offer."
What's on the menu?
The restaurant's acclaimed roast dinner includes a 12-hour roasted sirloin and roast chicken, served together on a sharing board, accompanied by roast potatoes, Yorkshire pudding, roasted carrots, green beans, parsnips, cauliflower cheese and gravy.
Vegetarians are also catered for with a mushroom wellington complete with all the trimmings.
Both roast diners can be enjoyed for a price of £19.95.
Due to popular demand, the restaurant is extending its Sunday roast offering by three hours, running from 12pm to 7pm, starting from 4 November.
A foodie hotspot
The roast dinner award is just the latest the restaurant has claimed, having also recently been named Best Newcomer at the Yorkshire Life Food and Drink Awards.
The restaurant prides itself on its varied food menu, with starters and desserts changing regularly to ensure diners always have something new to try.
Previous starters have included sweet potator and chorizo hash with fried egg, and salt cod fish cakes with pickles and lemon mayonnaise.
Desserts, meanwhile, have included sticky toffee pudding with vanilla ice cream, tonka bean panacotta, and chocolate and cherries.
And with two courses available for £22.50, or three for £26, it offers good value for money.
Healy added: "It's been a rollercoaster of a year for us and to already have a UK-wide competition win, and an award under our belts in our first six months, is a huge achievement."