Sauce:

mince similar amount of garlic, ginger and leek (or grass leek), mix in enough oil so that everything is covered, add in salt (to taste) and mix well

Mussels:

put mussels into boiled water, cook until the shells have opened up (those that don’t even open up a crack are probably the dead ones, you can throw them away), take them out of the water and open them into halves

place the halves into a oven form, add the sauce onto them, then on top a small piece of cheese, finally put the form into 200C preheated oven and bake until the cheese has melted and become golden.