First, give the razor clams a good wash in cold salted water, then leave them in the water for 15–20 minutes to expel any sand.
You don’t want to cook too many clams at once – if they are squashed they won’t have room to open. Place around 5 clams on a flat tray or griddle (you won’t be able to fit many in a round pan) and put on a medium-high heat. Drizzle a little bit of olive oil on top and leave them to open. Making sure they stay nice and flat, turn them over and cook them for 1 minute.
Squeeze over the lemon juice, remove to a long tray, season with salt and pepper, and finish with the ajillo.