I used fresh king salmon scraps for these cakes, but really any salmon, trout or other fatty fish (mackerel, freshwater drum, jacks, bluefish, etc.) will work well here. And obviously, since this is based off a crab cake recipe, crab with do well here, too.
Mix everything together in a bowl except the crushed Saltines, Wondra flour and oil.
To make the horseradish cream, mix everything together well. You can tinker with the ingredients as needed. Remember you want to be able to drizzle this on, so it shouldn't be too thick.
Heat enough oil to come up about 1 inch up the sides of a heavy pan; I use cast iron. Heat it to between 325°F and 350°F.
While the oil is heating, add enough of the crushed Saltines so that the cakes will come together. Start with 1/4 cup. You might need more, but you won't need less. Form the cakes with your clean hands -- wetting them every so often helps a lot -- and set them aside. Mix the remaining crushed Saltines with the Wondra flour.
When the oil hits temperature, coat the cakes in the flour-Saltines mix and fry until golden brown on both sides, about 3 to 4 minutes per side. Serve with a salad and some horseradish cream.
Video
Notes
NOTE: I put the sleeve of Saltines in a heavy freezer bag and wail on it with a rubber mallet. You need to do something other than crush them in the sleeve they come in, because it will burst open. Ask me how I know.
Keys to Success
Use any sort of raw salmon or trout here. Char is good, too, and if you are in a non-salmon or trout area, try this with tuna or bluefish or mackerel or jacks. Or, you know, crab.
Make sure your oil is hot. Don't skimp on this or your cakes will be greasy.
The horseradish cream will keep a week in the fridge.
If you want to store these cakes for later, go ahead and make them all, then let them cool. You can reheat them in a toaster oven or refry them briefly. Once cooked the first time, you can freeze them.