This easy and satisfying fish dish features a crunchy topping that does three things: It has great flavor in the classic Moroccan combination of lemon, olives, and herbs; it provides a crunchy textural contrast to the soft fish; and it keeps the fish moist by sealing in steam. A super easy and flavorful finish of lemon-infused oil and a bed of spinach make this a weeknight main dish elegant enough for a party, too.

• Heat the oven to 425 degrees F. Stir together the mayonnaise and mustard and set aside.
• In a small bowl, combine the breadcrumbs, olives, parsley, 2 tsp. of the olive oil, 1 1/2 tsp. of the lemon zest, a big pinch or two of ground cumin, and a pinch of salt. Stir to combine thoroughly.
• In a separate small bowl, combine 2 Tbs. olive oil with the remaining 1 tsp. lemon zest.
• Rub a shallow baking dish (we suggest 9×13) with 1 tsp. of olive oil. Arrange the lemon slices in the baking dish and top each with a piece of fish. Season the fish with a little salt and pepper. Coat the top and sides of the fish with the mayo-mustard mixture. Mound and pat the breadcrumb mixture over the top and sides of the fish until well-coated.
• Roast the fish for 20 to 22 minutes, or until the crust on the fish is deeply golden brown.
• In a large skillet, heat 1 to 2 tsp. olive oil over medium heat. Add the baby spinach and a pinch of salt, and cook, stirring and flipping with tongs, until wilted, about 2 minutes.
  Transfer the spinach to four serving plates, drizzle with a little of the reserved lemon oil, and top with a piece of fish. Drizzle a little more lemon oil around and over each piece of fish. Serve right away with lemon wedges, if you’d like.