Place the red onions in the vinegar the night before
Chop red onions and put in vinegar night before. Fire up grill as hot as possible. Open the live razors through 1 side of the shell, drain on kitchen paper and lightly oil with neutral oil. Push each razor briefly with open side on grill until grill pattern appears. Turn over and wait for fish to loosen slightly. Place on a platter and drizzle with olive oil and add a little of the onion with vinegar. Crumble some parsley over it and finish with turn of pepper mill and fleur de sel.
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 poking them open, 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