Baked Scallops Gratin. Original recipe from the Camino de Santiago.

What ingredients do I need to make baked scallops?
Scallops in their shell. If you buy the schnitzel you can make the recipe in containers suitable for baking.
White wine.
Onion.
Olive oil and salt.
Bread crumbs.
With these ingredients, you can now make the recipe. I added a little crushed tomato, garlic and parsley, just like my mother-in-law does.