Hake is a type of catfish, so use it any way that you would a soft fleshed white fish (it cooks fast and doesn't have much flavor on its own). Some suggestions (other than frying it) include sauteing it with veggies, grilling it lightly with lemon and olive oil, fish stew.
I accidentally got some from the supermarket and got it home, cooked up some, and thought, "hrm, this tastes like catfish...I wonder if it is related." After a quick Google search I found out why--it is catfish! Because of this, beware if you follow the "no scales" rule for fish--catfish are off limits.