Almost like the Rendezvous version

Steve Johnson of Rendezvous in Central Square has a way with fish cakes. Years ago, I ate his ethereal bluefish cakes at Mercury Bar, where he was cooking, and wherever he went after that, he always put them on the menu.

I had his bluefish cakes again on Saturday night at Rendezvous -- they're delicious! -- and decided it was time to go into the kitchen. Steve makes fish cakes with all the ingredients already cooked (rather than raw fish cakes). After cooking the fish, he adds spicy mayonnaise, lots of sauteed vegetables, and shapes the cakes and browns them.

They couldn't be easier. You can use leftover grilled or broiled salmon, or plain white fish. Serve the cakes with cucumber salad or cucumber-mint relish. I suggest making extra spicy mayonnaise to use as a sauce, as instructed here.

Bluefish cakes with spicy mayo
Serves 4 as an appetizer

1 pound boneless bluefish
Olive oil (for sprinkling and frying)
Salt and pepper, to taste
2 tablespoons olive oil
1 jalapeno chili pepper, cored, seeded, and chopped
1 medium onion, finely chopped
1/2 bulb fresh fennel, finely chopped
1 stalk celery, finely chopped
1 1/2 cups mayonnaise
2 tablespoons sriracha or other hot sauce
2 slices (1-inch thick) French bread or 1 small dinner roll, torn up

1. Set the oven at 400 degrees. Set the fish in a baking dish (skin side up). Sprinkle with oil, salt, and pepper. Roast the fish for 12 to 15 minutes or until it is cooked through. Leave to cool. Flake the fish, discarding the skin and any bones.
2. In a large skillet, heat the oil. When it is hot, add the chili pepper, onion, fennel, celery, salt, and pepper. Cook, stirring often, for 10 minutes or until the vegetables are softened.
3. Meanwhile, in a bowl, whisk the mayonnaise with 1 tablespoon of the hot sauce. Taste for seasoning. Add the remaining hot sauce, 1 teaspoon at a time, until it is the right heat for your taste. Transfer 3/4 cup of the mayonnaise to a serving bowl.
4. In a food processor with the motor running, pulse the bread into crumbs. Add the fish and pulse until it is well mixed. Add the onion mixture and remaining 3/4 cup of the mayonnaise. Pulse until well mixed.
5. Remove the work bowl from the processor stand. With your hands, shape the fish mixture into 4 patties.
6. In a large nonstick skillet, heat enough olive oil to barely cover the pan. When it is hot, fry the fish cakes for 5 minutes on a side, turning once, until they are crisp and golden. Serve with the spicy mayonnaise. Adapted from Rendezvous