From Claire Lassam's story, I Married An Onion.

Serves lunch for 2

• 2 Tbsp (30mL) butter, divided
• 2 lbs (1kg) yellow onions, peeled and thinly sliced
• 4 thick slices of sourdough bread
• 7oz (200g) aged cheddar cheese, sliced
• Dijon, to taste
• salt and pepper

In a medium saucepan over medium-low heat, melt 1 Tbsp of butter. Add the onions and salt, and cook until they are soft and the liquid has evaporated.

Turn the heat to low, and continue to cook until the onions have turned a mahogany brown. This will take several hours, but you only need to stir every 45 minutes or so.

Remove from heat, and store in a jar. They will last about a week.

Use the remaining butter on one side of each bread slice. 

Spread the onions on the unbuttered side of the bread, then layer on cheese. Put the other piece of bread on top, and repeat with remaining ingredients, forming two sandwiches with butter on the outside.

In a frying pan over medium heat, cook the sandwiches until the outsides are golden brown and the cheese inside has melted.

Remove the sandwiches and slice in half, serving lots of Dijon on the side for dipping.