Wipe the mushrooms clean and slice. Heat a pan over medium heat and spray with non-stick spray. Add mushrooms and spinach cook for 5-10 minutes, until tender. Set aside.
Bring a pot of water to a simmer. Break egg and drop in simmering water. Poach for three minutes or until done. Remove with a slotted spoon and drain on kitchen paper.
Toast bread in toaster, heat the beans, add sliced cheese to the toast.
Pour beans over toast, add the egg, mushrooms and spinach.