1-First Step: Get the heat going and mix the crumb topping Preheat your grill or broiler on high. If you plan to use the oven version, set it to 220 degrees Celsius or 390 degrees Fahrenheit. While the heat comes up, combine the crumb ingredients in a bowl: 1/2 cup panko breadcrumbs, 1 tablespoon finely chopped parsley, 1/3 cup finely grated parmesan, 1 minced garlic clove, 1 tablespoon olive oil, and a pinch of salt. Stir until the mixture looks evenly coated and slightly clumpy. That little bit of olive oil helps the topping brown into a lovely crisp layer.

2-Second Step: Season the fish and add the mustard Pat the 2 fish fillets dry if needed, then season both sides with salt and pepper. This is a small step, but it makes a big difference in the flavor. Next, spread 2 tablespoons of Dijon mustard on the top of each fillet. If you are using mayonnaise instead, spread it in the same way. The coating should be thin but even, so the crumb mixture will stick well without sliding off.

3-Third Step: Press on the crumb coating Place each mustard-coated fillet into the breadcrumb mixture, mustard side down, and press firmly so the crumb adheres. Turn the fish gently if needed and pack on any loose bits. You want a nice even crust, not a thick pile. This is what gives parmesan crumbed fish that satisfying crunch when you cut into it.

4-Fourth Step: Prepare the skillet and start cooking Spray the crumbed top lightly with olive oil spray. Then heat 1/2 tablespoon oil in a skillet over high heat. A preheated skillet gives the base a better sear and helps the fish hold its shape. Once the oil is hot, place the fillets in the skillet carefully. This quick pan start helps the fish crisp underneath before it goes under the grill or broiler.

5-Fifth Step: Finish under the grill or broiler Cook the fish under the grill or broiler for 5 to 6 minutes, or until the crumb is golden and the fish is cooked through. The fish should flake in the center when gently tested with a fork. If your fillets are about 2 centimeters thick, this is usually the perfect timing. For thicker pieces, switch to the oven method so the fish cooks all the way without burning the top.

6-Final Step: Use the oven option if needed and serve right away For the oven version, bake the fish at 220 degrees Celsius or 390 degrees Fahrenheit for 10 to 12 minutes, then finish under the broiler for a golden crumb. This works especially well for fillets thicker than 2 centimeters or 4/5 inch. Serve immediately with lemon wedges. The fresh lemon juice cuts through the rich parmesan topping and makes the whole dish taste bright and fresh.