A classic Hawaiian dish! And not one you find very often in the UK.
Make hamburger patties from ground beef (choose a fairly high fat content for this – the low-fat varieties can get a little dry!):
sauté finely chopped onion until softened and add to the ground beef, together with a beaten egg, 1 tsp Worcestershire sauce and
enough panko breadcrumbs to make everything stick together nicely, season well with a little sea salt, and plenty of freshly-ground
black pepper, and form into oval patties. Chill in the refrigerator for 30 minutes. Make the gravy by frying chopped onions until
translucent, then add sliced mushrooms and fry until starting to brown. Sprinkle over a Tbs plain flour and add a cup of good beef
stock (the little jelly tubs are good), a Tbs Worcestershire sauce, a Tbs soy sauce, stirring and simmering until thickened. Keep warm
while you cook some rice and the burgers. Press the centre of each patty to make an indentation (they will rise with heat), then fry
in a little oil until well browned on each side and cooked through. Serve over white rice, pour over some mushroom gravy and top
everything with a fried egg. Garnish with a grind of pepper and chopped spring onions.