Fill a stock pot 2/3 full with water and bring to a boil.
Peel potatoes and cut into cubes. Add the cubed potatoes to the boiling water. Cook until tender and drain. Mash the potatoes, do not add anything like butter or milk. Just mash the potatoes by themselves.
Heat butter in skillet over medium-high heat until foamy. Add garlic and green onions and saute for 2 minutes. Remove from skillet and set aside to cool.
To the mixing bowl with the flaked fish, add the Old Bay seasoning, half of the mashed potatoes, garlic salt, whisked egg, reserved onion mixture, and bread crumbs.
Use gloved hands to mix everything together. If needed, add remaining mashed potatoes, enough so that you can form patties from the mixture.
Form fish mixture into patties.
Add enough oil to the skillet to come about 1/2-inch up the sides. Heat to 350 F.
Place patties into the hot oil and cook for 4-5 minutes per side, or until golden brown. Remove to paper towels to drain.
Cod is the star of the show but you can substitute with just about any white-fleshed fish such as haddock, bluegill, tilapia, or grouper. Check out our recipe for fish cakes if you're looking to use salmon! Be sure to use cooked and cooled fish for this recipe.
If you have raw fish, here's quick instructions for baking cod in the oven:
Preheat the oven to 400 F. Line a baking pan with parchment paper.
If frozen, thaw the filets and pat dry with paper towels.
Rub filets with olive oil and season with salt and pepper (we also like to add Old Bay seasoning).