Preheat the barbecue using the plancha /teppanyaki area if you have one or a griddle pan over medium heat.
Flatten or smash the burger to be able to cook them rapidly.
Once the barbecue and the flat cooking pan are smoking hot and ready, drizzle some oil and add the burgers.
Cook on both sides for 2 minutes until nearly cooked through. Add the onions and allow to cook for a further 30 seconds or so. With a metal burger lifter or spatula , at this stage, chop the burger and onions together, keeping each portion in the same area of the pan.
Add the cheese slices over and continue to cook with a lid on for a further minute or so until the mixture is cooked to your liking and cheese melted.
Toast the buns and spoon some Marie rose sauce over each side.
Add a slice of salad leaves and tomatoes slices.
Lift the chopped cheese on the buns and top with some jalapenos and the top of the buns.