The story
Nestled in the heart of Borough Market, Kappacasein has earned a stellar 4.6-star rating for its unapologetically British, casual approach to street food. This small counter serves one standout item that has become a local legend: a grilled cheese sandwich built with Montgomery cheddar on Poilâne sourdough.
Food vlogger Mark Wiens calls it “next-level,” praising the “perfect crispy-oozy texture” and the addition of caramelized onions. The combination of sharp, melting cheddar and tangy sourdough creates a deceptively simple but masterful bite. For anyone exploring London’s market scene, Kappacasein’s grilled cheese is the kind of no-fuss, high-reward stop that defines the best of Borough’s food stalls.
Synthesised by AI from every creator’s review. First reviewed 2026.
Most-loved dishes
AI summary of what 1 dish mentions say about the food
Kappacasein’s legendary grilled cheese sandwich is a decadent, oozy triumph that earns ecstatic praise. The overall vibe is pure, unpretentious comfort, delivering a simple but transcendent experience.
“This grilled cheese sandwich has reached a mythical status level. It is like one of the gold ticket items that you have to try. They're using Kappacasein British cheese. He adds in a mountain of grated cheese, mostly Montgomery cheddar. It grills in the toaster. The cheese just oozes out so it melts in the center. The bread is so thin, but then you have the oozy cheese in the center and then you have the crispy cheese on the edges that spewed out and kind of crustated onto the sides of the bread. And then you also have the onions and the leeks on the inside. This is one of the world's great grilled cheese sandwiches. That Montgomery cheddar it starts with the cheese that has such an incredible flavor complexity, just enough saltiness, but taken to the next level because of the toasting technique and because the cheese is shredded rather than sliced so it allows it to seep out and coat onto the sides of the bread and crustate. Creating this crispy oozy cheese with just enough onions to offset or change the flavor. It's a next level grilled cheese.”
What creators say
1 creator has covered Kappacasein. Most active: Mark Wiens
Kappacasein serves a legendary grilled cheese sandwich with Montgomery cheddar on Poilâne sourdough, featuring a perfect crispy-oozy texture and caramelized onions — a next-level Borough Market classic.
Dishes mentioned
Grilled Cheese Sandwich
This grilled cheese sandwich has reached a mythical status level. It is like one of the gold ticket items that you have to try. They're using Kappacasein British cheese. He adds in a mountain of grated cheese, mostly Montgomery cheddar. It grills in the toaster. The cheese just oozes out so it melts in the center. The bread is so thin, but then you have the oozy cheese in the center and then you have the crispy cheese on the edges that spewed out and kind of crustated onto the sides of the bread. And then you also have the onions and the leeks on the inside. This is one of the world's great grilled cheese sandwiches. That Montgomery cheddar it starts with the cheese that has such an incredible flavor complexity, just enough saltiness, but taken to the next level because of the toasting technique and because the cheese is shredded rather than sliced so it allows it to seep out and coat onto the sides of the bread and crustate. Creating this crispy oozy cheese with just enough onions to offset or change the flavor. It's a next level grilled cheese.
