The art of making a good toasted sandwich, I think, relies on being resourceful and inventive. It's about rummaging through your fridge and pantry and creatively using the odd bits and pieces hanging around. It's the skill of using some leftover roast or cuts of meat with a bit of cheese and a scraping of pickle or chutney and transforming them into a tasty creation. It's about the art of construction. While anything goes, I have a few little tricks, too. The mustard goes on the ham - NOT the bread - and the salt and pepper should go on the tomato, not the cheese. Lettuce makes a fine buffer between beetroot and bread, because soggy is not good.
2 slices of soft white bread
slices of good leg ham
slices of gherkin or cornichons (French baby gherkins)
Butter two slices of soft white bread. Place a couple of slices of good leg ham on one and spread thinly with Dijon mustard.
Top with a few slices of gherkin or cornichons (French baby gherkins), a little cracked pepper and finish with a decent slice of gruyere cheese.
Top with the other slice of bread, butter both sides and toast in a jaffle or sandwich press.
Alternatively, pan-fry the croque monsieur in a non-stick frying pan over a medium heat, turning until each side is golden brown.