The secrets to perfecting it? First, use the right “glue.” If you’ve got the time and patience, a traditional breading (flour, egg and breadcrumbs) will work, but a far less messy and time-consuming binder is mayonnaise. It brings a bit of richness to the fish and spreads onto the fillets with a spatula so you can keep your hands clean. Second, season everything. Mix the mayonnaise with a little lemon zest, lemon juice and pepper to boost its flavor. To season the breadcrumbs, stir in a generous tablespoon of fragrant herbes de Provence and fruity extra-virgin olive oil to complement the mild flavor of the fish. The seasoned crumbs stick perfectly onto the mayonnaise-slicked fish.
All that’s left is to pop it in the oven and bake. The foolproof way to know whether the fish is finished is to use an instant-read digital thermometer (the temperature should register between 135 and 140 degrees), but if you don’t have one, simply give the fish a nudge with a fork — it’ll flake when it’s finished.