Prepare you ingredients by slicing the mushrooms and garlic, and chopping the parsley. Keep one garlic clove whole to use later.
Put the slice of bread and the tomatoes under the grill - keep an eye on these whilst you fry the mushrooms.
Heat a frying pan and add a knob of butter. when just melted, add the garlic and mushrooms and fry until soft and browned (approximately 5 minutes).
Season with a sprinkle of sea salt and stir in half the chopped parsley.
Take the slice of bread out from the grill when toasted and rub with the extra clove of garlic. When coated, tip over the mushrooms and top with the grilled tomatoes. Finish with a sprinkle of sea salt and the remaining parsley.