Preheat oven to Gas Mark 6, 200°C (400°F). Line a large baking tray with parchment paper. Brush a little of the melted butter over the parchment paper. Place the breadcrumbs in a shallow dish with the grated cheese and parsley. Place the flour and egg in separate shallow dishes.Season the hake with a little salt and black pepper. Dip the hake, one piece at a time, into the flour, shake off the excess, then dip into the egg and finally into the breadcrumb mixture. Place on the baking tray. Brush the remaining melted butter over the top and sides of the fish. Place in the oven and bake for 15 minutes or until cooked through.Meanwhile make the Yogurt Tartar Sauce: Place yogurt, mustard, capers, gherkin, parsley, salt and pepper in a small bowl. Mix well to combine.
Serve the sauce with the crispy hake, tender stem broccoli and sautéed potatoes.