First rinse the cockles under some cold water to remove any sand. The ones that start to float you need to throw, these are bad. Now drain them for at least 5 minutes. Meanwhile cut the onion in half and clean it. Then chop it. After that pour a drizzle of oil into a big pan and glaze the onions on a medium heat with the bay leaves. When they start to color directly add the cockles and pan fry them for 30 seconds. Then deglaze the pan with the white wine and boil them till the cockles open up. This takes around 1 minute. Now drain them and keep the liquid for later. Let them cool down completely in your fridge. Once cold remove the cockles from the shells. Keep the shells for later to present the amuse. If you don’t want to do this just throw them. If you do transfer them into a pan and cover them completely with water. Now boil them for 1 minute. Then drain them and repeat it till the shells are completely clean. After that transfer them onto a tray and let them dry at room temperature. Now back to the cockles. You can already eat them like this, but I like to clean once more. For this cut the orange part of the rest. Then transfer them into a bowl and pass the cooking liquid through a kitchen paper on the cockles. This will prevent them from drying out. Keep them in your fridge.