- Preheat oven to 180°C/360°F
- Toss the burger buns in oil and salt then bake for roughly 10 minutes, or until the burger bun croutons are well browned and crispy.
- In a saucepan heat the butter until foaming then add the flour. Gradually whisk in the milk until the sauce thickens and starts to simmer, then stir in the cheeses.
- Meanwhile, fry the burger patties to your taste and set aside.
- Build up layers of the burger bun croutons, patties, gherkins, tomatoes and some lashings of tomato ketchup and American mustard. Pour over the cheese sauce then add a final layer of gherkins.