This is one of the dinner saver soup with few ingredients and really quick to make.
Slice the mushrooms.
In a saucepan put butter and blend with flour. Cook slowly stirring until they incorporate together well.
Add grated onion and sliced mushrooms with 1 cup of water. Stir to thicken.
Mix cream, cheese, salt and pepper. Cook the soup under medium heat until the soup becomes smooth and velvety.
Drizzle grated cheese over the hot soup and serve immediately.