You can make this with any white fish. Obviously cod, haddock, pollock and hake, but also bass, walleye, black seabass, Pacific rockfish, lingcod, etc. I bet it would work with catfish, too. Serve with potatoes, bread or rice and a full-bodied white wine or dry cider.
Salt the fish well and set aside for 10 to 20 minutes. Heat the olive oil over medium heat in a large, wide pan that can hold all the pieces of fish.
Saute the garlic slices for a minute or two, until they just start turning golden. Remove them as best you can. It's OK if a few escape you.
Put the fish skin side down in the pan and cook gently over medium-low heat for a minute or two. Turn the fish and cook for another 2 to 4 minutes, or until the fish is mostly cooked. Turn the heat off and remove the fish for now.
Start swirling the pan. You want to gently agitate the olive oil and juices from the fish into an emulsion. This should take about 5 minutes and no more than 10 minutes. One way to help this along is to whisk it with a strainer, as you can see in the video. As the emulsion comes together, add back the garlic as well as the crushed chiles, if using. It will eventually look like a salad dressing, and if you keep stirring it while the whole thing cools, it will set up into a mayonnaise-like sauce. It's up to you if you want it this way.
When you are ready, pour the sauce over the fish, sprinkle some dried herbs on there and serve.
NOTE: While not strictly necessary, the skin of fish contains a lot of collagen, which helps the sauce emulsify more easily than skinless fish.