Photo: Kolforn (CC BY-SA 4.0) via Wikimedia Commons · source
London's market toastie: three cheeses and sweet, soft onion and leek pressed into sourdough until the cheese leaks out and fries crisp at the edges. The same pressed-sandwich idea runs from Montreal's Wilensky Special to New Orleans' collard green melt.
100 g (1 cup) grated mature cheddar (Montgomery if you can find it)
60 g (2/3 cup) grated Comté or Gruyère
60 g (2/3 cup) grated Ogleshield, raclette or another good melting cheese
1 small leek, white part, thinly sliced
1/2 small white onion, thinly sliced
1 small clove garlic, finely chopped
2 tbsp butter, plus soft butter for the bread
How to make it
Soften the alliums (8 min): Melt 1 tbsp butter and cook the leek, onion and garlic with a pinch of salt over medium-low heat until soft and sweet but not brown, 8 minutes. Cool a little.
Mix the cheese (1 min): Toss the three cheeses together.
Build (2 min): Butter the outside of each slice. On 2 slices (butter side down) pile half the cheese, the leeks and onions, then the rest of the cheese, letting some spill to the edges. Close.
Press and cook (6 min): Cook in a heavy skillet over medium heat with another heavy pan pressing on top, 3 minutes a side, until deep golden and the cheese has run out and crisped against the pan. (A sandwich press works too.)
Rest 1 minute, cut in half and eat while it's still stretching.
Tips
The leaked, fried cheese at the edges (the 'frico') is the best part; let it happen.
Montreal variation: grilled beef salami and bologna with mustard on a pressed roll, no cheese at all.