Mashed Potato Fish Cakes
Got leftover mashed potatoes? This recipe for potato fish cakes is the best way to give them a new life! They're crisp on the outside, tender on the inside and perfect for a simple, yet satisfying dinner.
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If it's the day after Thanksgiving or another holiday, these mashed potato fish cakes are a clever way to repurpose leftover mashed potatoes! It's also a perfect way to use up leftover fish, but they can be made with fresh potatoes and fish, too.
If you plan ahead, you can make fish and mashed potatoes for dinner one night and then make these easy fish cakes the next day!
This recipe is inspired by the fishcakes my grandfather used to make, which were also made with mashed potatoes. I never learned his recipe, but these taste pretty darn close. They're similar to New England cod cakes, since that's where he was raised!
These are great with a little squeeze of lemon but also go nicely with cocktail sauce, homemade tartar sauce or even just a little drizzle of melted butter over top.
You can make these fish potato cakes with any type of fresh fish, including leftovers or even canned. Ideally something flaky, but also firm.
Fresh cod is classic along with haddock and pollock, but this will work with almost anything. I had a bag of frozen tilefish that our neighbor caught this summer, so that's what I used.
The amount of breadcrumbs will ultimately depend on how moist or fatty your mashed potatoes are. If they contain a lot of butter and cream, they will need more breadcrumbs to bind them together. I used ¼ cup, but you may need to add more.
I also like to coat the fish cakes in some breadcrumbs before pan frying to give them an extra crispy outer coating. But if you want to make these even easier, you can skip this step and fry without it.
Want more great fish recipes? Try my crispy Panko Crusted Fried Fish, this easy Lemon Herb Baked Fish for a cozy dinner, or my comforting New England Fish Chowder for a classic bowl of soup.
Why This Recipe Works
- A great way to repurpose mashed potatoes and/or leftover fish in a new way.
- Can be made with different types of fish, whether fresh, cooked or canned.
- The cakes hold together nicely, stay tender inside and develop a crispy, golden crust.
Ingredients for Potato Fish Cakes
Fish - Any type of firm but flaky fish will work. You can even use canned tuna or salmon in a pinch. Choose responsibly sourced fish whenever possible.
Mashed potatoes - Leftover mashed potatoes work best, but you can boil a few potatoes and mash them with a little bit of butter, salt and pepper.
Breadcrumbs - Plain breadcrumbs work well, but Italian seasoned crumbs or panko breadcrumbs work well too.
Seasonings - I keep the seasoning simple with shallots, garlic and parsley, but you can add more herbs or spices if you like. Finely diced celery, bell pepper, scallions, thyme or dill would all be great.
Egg - Helps bind the mixture so the patties hold together in the pan.
*Find the full ingredient list in the recipe card below!
Helpful Equipment
- Large skillet
- Mixing bowls
- Measuring cups
- Fork
- Baking sheet
- Parchment paper
- Thin spatula
- Paper towels
How to Make Potato Fish Cakes
- Pat the fish dry and season lightly with salt and pepper.
- Heat 2 tablespoons of butter in a large skillet or frying pan over medium heat. Add the fish and sauté until just cooked through and beginning to flake, about 4 to 5 minutes per side, depending on thickness. Be careful not to overcook.
- Transfer to a plate and let cool slightly, then flake into medium pieces with a fork.
- Wipe out the skillet and return it to medium heat. Add the remaining tablespoon of butter, then sauté the shallot until soft and translucent, about 3 minutes. Add the garlic and cook just until fragrant, about 30 seconds. Do not let them brown. Transfer to a large bowl and let cool.
- Add the mashed potatoes, parsley, egg, ¼ cup breadcrumbs, salt and a few grinds of black pepper to the bowl. Mix to combine.
- Add the flaked fish and gently mix, keeping some larger pieces intact. If the mixture feels too loose, add more breadcrumbs 1 to 2 tablespoons at a time until it firms up.
Pro Tip: You may need more or less breadcrumbs depending on the consistency of your mashed potatoes. If they were made with a lot of milk or cream, you will need more breadcrumbs to bind the mixture.
- Divide the mixture into 8 portions and shape into patties about ½ inch thick. Place on a parchment lined tray and chill for 15 to 20 minutes to firm up.
- Spread the remaining ¼ cup breadcrumbs in a shallow bowl or plate. Lightly press each fish cake into the crumbs on both sides.
- Preheat the oven to 375°F. Wipe out the skillet and place over medium high heat. Pour in enough oil to coat the bottom, then add the fish cakes in batches.
- Fry until golden and crisp, about 3 to 4 minutes per side, adjusting heat as needed.
- Drain briefly on paper towels, then transfer to the oven and cook for 10 minutes.
- Serve warm with plenty of lemon wedges and a little melted butter drizzled over top.
Tips for Success
- You can skip the first step by using leftover cooked fish instead.
- The mixture should be moist but firm enough to hold its shape. Add breadcrumbs as needed to achieve the right consistency.
- For the best results, chill the patties before frying so they hold together in the pan.
- Leftovers reheat nicely in a 350°F oven or air fryer for 10-12 minutes until warmed through and crisp.
Variations
- Use cod, haddock, pollock, sea bass, tilefish, taug, barramundi, halibut, grouper, mahi mahi, any flaky white fish or even fresh salmon.
- Try using canned tuna or salmon if you don't have leftover or fresh fish.
- Add more herbs like tarragon, dill or thyme, or try lemon zest to add brightness.
- Add finely minced vegetables like celery, bell pepper or scallions for crunch.
- Use panko bread crumbs for an extra crunchy crust.
- Substitute fish with lump crabmeat to make potato crab cakes.
What to Serve with Fish Cakes
Serve these warm as a main course with a bright squeeze of lemon juice and a few fresh herbs for garnish or as a light lunch with a simple side salad with balsamic vinaigrette.
Try them with this Spinach recipe with butter and parmesan, these crispy Brussels Sprouts with Pecorino and Herbs, Sicilian-style Roasted Cauliflower or crisp Green Beans with Shallots and Pancetta for a balanced plate.
How to Store and Reheat Fish Cakes
Store leftovers in an airtight container for up to 3 days. Reheat on a lined baking sheet in a 350°F oven or air fryer until warmed through and crisp, or pan fry them again.
You can freeze them in a single layer on a tray, then transfer to a freezer container once solid. Reheat from frozen in the oven until crisp and hot in the center.
FAQs
Yes, you can make ahead the base of these easy potato fish cakes. Prepare the mixture and shape the patties, then keep them chilled on a lined baking sheet for up to 24 hours before cooking.
They may need more breadcrumbs. Mix in a little more until the mixture holds together when pressed.
Yes. Arrange the patties in a single layer, spray lightly with oil and air fry at 375°F until golden brown, flipping halfway.
Absolutely. Fresh chives, green onion, or spring onions add brightness. Finely diced vegetables work well too.
You can still make these easy potato fish cakes by mashing up freshly cooked potatoes, like Yukon gold. Boil them until tender in salted water for good measure, drain well, then mash while warm with a potato masher until smooth. Let them cool a bit so the mixture firms up, then continue with the recipe. The fish patties will hold together beautifully and taste just as good as if you had started with leftover mashed potatoes.
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Easy Potato Fish Cakes
Ingredients
- 1 pound white fish such as cod, haddock, or pollock, sea bass or tilefish, thawed if frozen
- 3 tablespoons unsalted butter divided
- 1 ½ cups leftover mashed potatoes
- 1 shallot minced
- 1 garlic clove very finely minced
- 1 tablespoon Italian parsley very finely minced
- 1 large egg
- ½ cup plain breadcrumbs divided, plus more as needed (see note)
- kosher salt to taste (amount depends on the saltiness of your potatoes)
- freshly ground black pepper to taste
- neutral oil for frying
- lemon wedges for serving
Instructions
- Pat the fish dry and season lightly with salt and pepper.
- Heat 2 tablespoons of butter in a large skillet over medium heat. Add the fish and sauté until just cooked through and beginning to flake, about 4-5 minutes per side, depending on thickness. Be careful not to overcook.
- Transfer to a plate and let cool slightly, then flake into medium pieces with a fork.
- Wipe out the skillet and return it to medium heat. Add the remaining tablespoon of butter, then sauté the shallot until soft and translucent, about 3 minutes. Add the garlic and cook just until fragrant, about 30 seconds. Do not let them brown. Transfer to a large bowl and let cool.
- Add the mashed potatoes, parsley, egg, ¼ cup breadcrumbs, salt and a few grinds of black pepper to the bowl. Mix to combine.
- Add the flaked fish and gently mix, keeping some larger pieces intact. If the mixture feels too loose, add more breadcrumbs 1-2 tablespoons at a time until it firms up.
- Divide the mixture into 8 portions and shape into patties about ½ inch thick. Place on a parchment-lined tray and chill for 15-20 minutes to firm up.
- Spread the remaining ¼ cup breadcrumbs in a shallow bowl or plate. Lightly press each fishcake into the crumbs on both sides, just enough to give a thin coating.
- Preheat the oven to 375℉. Wipe out the skillet and place over medium high heat. Pour in enough oil to coat the bottom, then add the fishcakes in batches.
- Fry until golden and crisp, about 3-4 minutes per side, adjusting heat as needed.
- Drain briefly on paper towels, then transfer to the oven and cook for 10 minutes.
- Serve warm with plenty of lemon wedges and a little bit of melted butter drizzled over the top.
Notes
- You can skip the first step by using leftover cooked fish instead.
- The mixture should be moist but firm enough to hold its shape. Add breadcrumbs as needed to achieve the right consistency.
- For the best results, chill the patties before frying so they hold together in the pan.
- Leftovers reheat nicely in a 350°F oven or air fryer for 10-12 minutes until warmed through and crisp.
