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Eric Akis: Mashed potatoes, rockfish a marriage made from fridge

Fish cakes are made with leftover mashed potatoes and bits of fresh B.C. rockfish
Savoury fish cakes are made with leftover mashed potatoes and bits of B.C. rockfish. ERIC AKIS Savoury fish cakes are made with leftover mashed potatoes and bits of B.C. rockfish. ERIC AKIS

I scanned my refrigerator the other day, looking for inspiration on what to make for dinner, and that cold cupboard was pretty bare. There were a few bits and bobs in my produce drawer, including some local asparagus, my usual, wide array of condiments, eggs, Greek-style yogurt and not much else.

Luckily, among the items I categorized as “not much else,” were some leftover mashed potatoes I served with roast chicken a couple of nights before. When cold and sitting in a bowl, they don’t exactly whet one’s appetite. But that changes when you imagine those potatoes added to another dish in a hearty and flavourful way.

For me, that often means using those cold mashed potatoes as the base for fish cakes, which I did for today’s recipe.

In this column, over the years, I’ve made mashed potato-based fish cakes with salmon, halibut and cod. But on this occasion I opted for B.C. rockfish fillets, because at my local seafood store they shimmered with freshness.

In retail settings, B.C. rockfish is also sometimes sold as Pacific snapper, despite not being related to “true” snappers caught in warm-water places such as the Gulf of Mexico. Rockfish has a mild and appealing, slightly sweet taste that works well in a fish cake served with tangy tartar sauce.

To make my fish cake recipe that serves two, a fillet of rockfish was cut into small cubes and mixed with a cold mashed potato mixture that was enhanced with green onion and Old Bay Seasoning, a classic seafood seasoning blend sold in small tins at many grocery stores. A bit of flour and an egg yolk were also added to the fish/potato mixture to help bind it together when cooked.

The fish/potato mixture was then formed into cakes, coated in panko (coarse breadcrumbs), and then fried in oil until golden and cooked through.

I mentioned above that I had some Greek-style yogurt in my refrigerator and decided to use it as the base for my tartar sauce, instead of the mayonnaise I would normally use. Like mayonnaise, it too has a tangy taste that works well in a tartar sauce flavoured with such things as chopped sweet pickles, capers and whole grain mustard.

To make a meal of the rockfish cakes, I served them with the local asparagus I had, which I steamed and lightly buttered. Instead of asparagus, you could also serve the fish cakes with a green salad or coleslaw.

Rockfish Cakes with Yogurt Tartar Sauce

Preparation time: 30 minutes

Cooking time: eight to 10 minutes

Makes: two servings

150 to 175 gram rockfish (also called Pacific snapper) fillet, any bones removed (see Eric’s options)

1 cup cold mashed potatoes (see Note 1)

1 green onion, halved lengthwise, then thinly sliced, widthwise

1 large egg yolk

1 Tbsp all-purpose flour

1/2 tsp Old Bay seasoning (see Note 2)

• salt, to taste

3/4 cup panko

3 Tbsp vegetable oil

• Yogurt Tartar Sauce (see recipe below and Eric’s options)

• lemon slices and dill or parsley sprigs, for garnish

Thoroughly pat the rockfish dry with paper towel. Cut the fish into thin strips. Now cut each strip into small, about 1/2-inch, cubes.

Place the potatoes, green onion, egg yolk, flour, Old Bay seasoning and salt in a bowl and mix to combine. Add the cubed rockfish and mix until well combined with the potato mixture.

Line a baking sheet with parchment paper. Spread the panko out on a sided plate. Set a quarter (about 1/3 to 1/2 cup) of the fish/potato mixture in the centre of the panko. Sprinkle the top and sides of it with panko, and then form and press the fish/potato mixture into a three- to three-and half-inch wide cake and set it on the baking sheet. Repeat these steps with the remaining fish/potato mixture, coating about 1/3 to 1/2 cup of it each time with panko. You will end up with four rockfish cakes.

Let the rockfish cakes firm up in the refrigerator at least 30 minutes before cooking them. (The rockfish cakes can be made to this point a few hours in advance. Keep refrigerated until ready to cook.)

To cook the rockfish cakes, place the oil in a large non-stick skillet set over medium, medium-high heat. When the oil is hot, fry the fish cakes until golden brown and the rockfish is cooked through, about four to five minutes per side. Serve two cakes per person, accompanied by the yogurt tartar sauce, and garnished with the lemon slices and dill (or parsley) sprigs.

Note 1: If you don’t have any leftover cold, mashed potatoes to use in this recipe, one large (about 11 ounce/310 gram) baking potato, when peeled, quartered, boiled until tender and mashed with 1 Tbsp milk, should yield the one cup needed here.

Note 2: Old Bay seasoning is a classic blend of herbs and spices often used to flavour fish/seafood dishes. It’s sold in tins in the herb/spice aisle of many supermarkets. If you can’t find it, your favourite seasoning salt/blend will also work in this recipe.

Eric’s options: If you can find or don’t wish to use rockfish, other types of fish, such as halibut and cod fillet, will also work in this recipe. If you don’t want to make yogurt tartar sauce, you could replace it with store-bought tartar sauce or your own favourite recipe for it.

Yogurt Tartar Sauce

In this twist on tartar sauce, thick, tangy yogurt replaces the tangy mayonnaise. Serve it with fish cakes and other fish/seafood dishes that would be enhanced with a dollop of tartar sauce.

Preparation time: 10 minutes

Cooking time: None

Makes: two servings

1/4 cup plain, thick, Greek-style yogurt

1 Tbsp finely chopped sweet mixed pickle or green relish

1 tsp capers, finely chopped

1 tsp chopped fresh Dill or parsley

1 tsp whole grain Dijon mustard, or to taste

1/4 tsp honey, or to taste

• lemon juice, Tabasco or other hot pepper sauce and salt, to taste

Place ingredients in a small bowl or jar and mix to combine. Cover and refrigerate this yogurt tartar sauce until needed. It can be made many hours in advance.

Eric’s options: Recipe could be doubled or further expanded if you desire a more generous amount of tartar sauce.

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Eric Akis is the author of eight cookbooks. His columns appear in the Life section Wednesday and Sunday.