Preheat the oven to 200°C.
Pour oil into a deep roasting tin until 2cm deep and heat in the oven until smoking.
Add potatoes to the hot oil, coat well, season with salt and pepper, and roast for 10 minutes.
Stir in garlic, tomatoes, chillies, and paprika, then roast for 30 minutes until potatoes are crisp.
Adjust seasoning, add more olive oil if dry, and garnish with parsley.
Place hoki steaks on a lightly oiled tray and season with salt, pepper, and lemon juice.
Mix cheese, mustard, and beaten eggs in a bowl until combined.
Divide cheese mixture into ten portions and press one onto each hoki steak.
Roast the fish for 10 to 15 minutes until the topping browns and fish is cooked.
Serve the hoki steak on top of a generous spoonful of patatas bravas.