Hot Hamburger Sandwich - Cooking like a Boss

Traditional Canadian comfort food. It's a burger on top of a slice of bread covered in gravy. Much nicer than it deserves to be! Serve with garden peas and chips.

7 medium onions	dice	fry in burger pan until golden	fry until mushrooms golden	melt	stir in	stir in	season	return burgers to pan	cover and simmer until cooked through	top
oil
14cups 3.31l 3312ml 5.83pint 221tbsp 662tsp mushrooms	slice
7tbsp 0.105l 105ml 21tsp 0.444cup 0.185pint butter
7tbsp 0.105l 105ml 21tsp 0.444cup 0.185pint flour
1312 ¹⁄₂ml 1 ⁵⁄₁₆l 87 ¹⁄₂tbsp 262 ¹⁄₂tsp 5.55cup 2.31pint beef broth
3 ¹⁄₂tbsp 0.052l 52 ¹⁄₂ml 10 ¹⁄₂tsp 0.222cup 0.092pint marmite
burgers
1750g 1 ³⁄₄kg 3.86lb 61.7oz minced beef	mix	form into 14 patties	brown	remove to plate
3 ¹⁄₂tbsp 0.052l 52 ¹⁄₂ml 10 ¹⁄₂tsp 0.222cup 0.092pint worcestershire sauce
3 ¹⁄₂tbsp 0.052l 52 ¹⁄₂ml 10 ¹⁄₂tsp 0.222cup 0.092pint garlic powder
salt
pepper
3 ¹⁄₂tbsp 0.052l 52 ¹⁄₂ml 10 ¹⁄₂tsp 0.222cup 0.092pint onion powder
3 ¹⁄₂ egg
oil
14 slices of white bread