Pat the haddock fillets very dry with paper towels. Lightly salt them and place in the fridge for 20 to 30 minutes for a quick dry brine.

Mince the garlic, chop the parsley, and zest the lemon.

Preheat the broiler on high and position the rack about 6 inches from the heat source.

In a small saucepan over medium heat, melt the butter. Let it foam and cook until golden brown with a nutty aroma. Remove immediately from heat.

In a bowl, combine the breadcrumbs, garlic, lemon zest, parsley, and a pinch of salt. Add the brown butter and mix until evenly coated.

Pat the fish dry again after dry brining. Lightly brush the tops with Dijon mustard.

Place the haddock on a lightly oiled sheet pan and season with pepper. Press a thin, even layer of breadcrumbs onto each fillet. Drizzle lightly with olive oil.

Broil on high for 6 to 9 minutes until the topping is golden and crisp and the fish reaches 125 to 130°F internally. Watch closely to prevent burning.

Rest for 2 minutes. Finish with fresh lemon juice and serve immediately.