Finely chop shallots and put in vinegar night before.
Fire up the grill as high as possible
Poke the razor clams open through one side of the shell (tip: if you don't succeed in opening them with a knife, put them on the grill for a while until they are slightly open)
Drain razors on paper towels
Brush the razor clams with the olive oil
Press razor blades onto the grill with the open side until a grill pattern forms
Flip the razor blades and wait for the fish to release a bit
Place them on a platter, drizzle with some more olive oil and add some of the pickled onion
Sprinkle the parsley over the razor clams and finish with salt and pepper to taste