I figured my visit to the new Bistro du Vin at 36 Dean Street in Soho would be uneventful. To update my top 10 burgers in London list I needed only to verify its burger was as good as the chargrilled sensation at the Bistro du Vin on St John Street. I was also curious to see if the chefs had addressed its instability issue. As good as the burger was it didn’t sit all that securely on its layered foundation of tomato, red onion and round lettuce hanging way out the sides.

The Soho version of Bistro du Vin burger, pictured at the top of this post, was an abomination. It arrived as you see it, with a wide crack extending from one side to the other. My initial guess was that a chef had cut the burger open to check it for doneness and broke the fat patty in half, spilling its juices. But the cooking process might have had something to do with its fragility. I finished the job with a steak knife, slicing the burger in two to analyse the damage. What a horror! The burger was impossible to pick up and eat, not that you’d want to. Its meat was hard, mealy and dry – nothing like the crumbly, juicy version on St John Street. It was seasoned with whole peppercorns, not the ideal texture for a burger, and nothing about it tasted right. I dropped the mostly uneaten burger onto its serving board and surrendered.

The hostess came by to ask me what I thought of the burger and I told her. She summoned Keith Shearer, the executive chef of MWB Group Holdings, which operates the restaurants at all Bistro du Vin and Malmaison locations as well as pubs like London’s Fox & Anchor.  Shearer explained he’d been forced to respond to the very real dangers of serving rare or even medium rare burgers. With steaks the exposed surface area of the meat gets seared and bad bacteria gets killed. But when beef is minced any surface contamination gets dispersed throughout the interior. If the burger is cooked medium-rare, as most Bistro du Vin diners want it, the internal temperatures are not sufficiently high to kill all bacteria.

Shearer’s solution is to fry cuts of beef before they are minced, ostensibly killing any bad stuff on the surface before it can be pushed to the interior. The burger is essentially cooked twice, a grave risk to good taste if not good health.

Shearer attributed the peppercorns in the mince and the deep crack in the burger to greenness – that of the young chef who prepared my burger. The restaurant only opened last week. The executive chef offered to prepare me a replacement himself, medium-rare. He raced to the kitchen and returned with a burger 12 minutes later. A photo of the dismal result appears below.