Mix the pre-chopped parsley and garlic in a small bowl. Add the zest of one orange and mix thoroughly. Set aside.
Grease the baking dish well with vegetable or any other oil. First, cover the bottom with grated carrots, spread the chopped onion on top in an even layer, then lay out the hake fillet. Add salt and pepper to taste. Place in a preheated oven. Bake for 40 minutes at 180 ℃.
Mix the grated cheese and sour cream thoroughly in a deep bowl. Spread the mixture evenly over the fish, top with sliced cherry tomatoes and bake for another 15 minutes.