Grill with a little butter on
Bake with tomatoes, or in home-made tomato sauce - keep the sauce fairly thick as liquid will come out of the hake as it cooks
Bake and then cover with any sort of sauce - parsley, hollandaise, cheese, beurre blanc etc
Haven't eaten hake for ages, but if I remember correctly, it can be fairly dry, so anything in a foil parcel or grilled/baked with a sauce should work.