As our appetite for more adventurous flavours and textures increases, the humble burger has become the star of the gourmet show. Buns are being infused with charcoal or replaced by scotch eggs, patties are experimenting with black pudding and goat, while watermelon pickle and kimchi are replacing ketchup. With gourmet burger sales predicted to grow by 19% by 2020 to £3.8 billion, it’s no wonder business website startup.co.uk has identified them as a key investment opportunity for 2016.

For the fourth year running, daily email Mr Hyde is celebrating the gourmet burger by offering 20% off in more than 750 restaurants nationwide on National Burger Day (Thursday 25 August). Download a voucher from nationalburgerday.co.uk then enjoy a specially created burger by Bleecker St Burger, Patty & Bun, Meat Liquor and more. In London, 18 of the capital’s best burger slingers will be at the National Burger Day party at Street Feast at Hawker House. Tickets go on sale 8am Wednesday 27 July and include a trio of American-themed beverages. Just tell yourself you’re doing “research” for your next business investment…

National Burger Day, Thursday 25 August; Street Feast at Hawker House, £16; nationalburgerday.co.uk; #nationalburgerday