1-First Step: Get everything ready Start by preheating your oven to 220°C if you are baking. If you plan to broil, move the rack so the fish sits about 15 cm from the heat source. Line a baking tray with parchment paper or lightly grease it, then set it aside. Take the fish fillets out of the fridge early so they can come to room temperature, which helps them cook more evenly. Pat the fish dry with paper towels. This matters more than people think. A dry surface helps the mustard stick and keeps the crumb topping from slipping off. Season both sides lightly with salt and pepper.

2-Second Step: Make the crumb mixture In a small bowl, mix together the panko breadcrumbs, finely grated parmesan, minced garlic, olive oil, pinch of salt, and parsley if you are using it. Stir until the crumbs look evenly coated and a little clumpy. That tiny bit of oil helps the topping brown and keeps it from tasting dry. If the mixture feels too loose, press it together with a spoon. If it seems too wet, add a small sprinkle of extra breadcrumbs. You want it crumbly but still able to stick together when pressed.

3-Third Step: Coat the fish Brush or spread about 1 tablespoon of Dijon mustard over the top of each fillet. You only need a thin layer. The mustard is there to help the crumb mixture stick and to add flavor, not to overpower the fish. If mustard is not your thing, mayo works too. It gives a milder finish and still helps the crumbs cling. Once the fish is coated, press the crumb mixture firmly on top of each fillet. Use your fingers or the back of a spoon to gently pat it down so it adheres well.

4-Fourth Step: Cook until golden Place the fish on the prepared tray. Give the crumb topping a light spray of olive oil, which helps it crisp and turn golden in the oven. Bake at 220°C for 10 to 12 minutes, depending on thickness, or broil on high for 5 to 6 minutes if your fillets are about 2 cm thick. Keep an eye on it near the end because the parmesan can brown fast. The fish is done when it flakes easily with a fork and reaches an internal temperature of 60°C. Thick fillets may need another minute or two. Thinner fillets may cook quicker, so stay close to the oven.

5-Final Step: Serve right away Let the fish rest for 1 minute, then serve immediately while the crumb topping is still crisp. This dish tastes best hot from the oven with a squeeze of lemon, a simple side salad, or steamed vegetables. If you want a cozy pairing, try it with something like parmesan risotto for a satisfying dinner, or keep it light with greens and roast potatoes.