You could consider hake an "everyfish." You know, the type of mild, white-fleshed variety you can do just about anything with – grilling, frying, roasting, steaming; you name it. A bit more mild than cod and quite flaky, hake pairs well with just about any side dish and gives you a lot of latitude for creativity and style.
Tomatoes, capers, onions and herbs, for example, make unctuous complementary ingredients to cook with hake fillets. If you want to go "dry," you can do that too. A little extra olive oil and you can re-create the taste and texture of pan-fried hake while you utilize the remaining oven space for matching sides like garlic roasted broccoli, oven-baked asparagus "fries," and crispy salt and vinegar "chips" made with fingerling potatoes. Start with the basic hake-bake technique:
Prepare: Hake fillets don't require any prep work themselves, other than patting them dry and seasoning them to taste with kosher salt and freshly ground black pepper (or your spices of choice). Also, if you buy a whole hake fillet (they weigh about 1 pound), you might want to cut it into halves or fourths to make serving easier.
If you plan to bake the hake with complementary ingredients, such as onions and capers, cut, slice and dice the ingredients as needed. Heat the oven to 375F, and brush the hake with olive oil or melted butter.
Place a few sliced onion or lemons (at least 1/4-inch thick) in the bottom of the baking dish; this elevates the fillets and contributes to better browning. After you arrange the fillets on the sliced onions or lemons, add the secondary ingredients around them. Crushed tomatoes, thinly sliced onions or shallots, minced garlic and basil make a classic combination to get you started.
Set the dish on the center rack and let the oven do its thing. A 3/4- to 1-inch-thick hake fillet takes about 15 to 20 minutes to roast, uncovered. When ready, the temperature of center of the fillet will be 145F, and its flesh will flake easily.
Squeeze a little fresh lemon juice over the fillets and spoon some of the side ingredients over the top. Garnish with freshly chopped parsley, if desired.
To steam hake in the oven, wrap it in parchment paper "en papillote" style, or use aluminum foil. Add a pat of butter or a few sliced vegetables, such as mushrooms and shallots, to create extra steam during cooking.
To oven-fry hake, add about 1/4 inch of olive oil to the dish (without other ingredients) and bake at 450F for 7 to 8 minutes, turning the fillet over halfway through cooking.