Set your oven to grill on hot hot hot and place a tray quite high in the oven but not the top shelf (too hot there!)
Slice the zucchini by cutting in half and then into longways. Chop the mushrooms in half and place on an oven tray and grill for about 10 minutes, if you need to brown it off a bit more - now use the top shelf.
Sprinkle with rosemary and salt and serve.
Sage can replace the rosemary. Also nice with lemon squeezed over the top.