Heat oil in a pan, take out your burger and fry until browned, flip to cook evenly. Cook in batches to avoid overcrowding. Set aside.

For the sauce: in the same pan melt butter, add in evaporated milk, soy sauce, beef broth cube, salt and pepper to taste. Mix well and cook this for 2 minutes.

Take it off the pan and strain. To remove excess bits. Set aside.

In the same pan saute mushrooms for a few minutes. Pour the sauce back in. Mix in the slurry. Simmer until the sauce has thickened so the sauce has slightly reduced.

Place these over the burger and enjoy!