Potato Casserole with Fish (Oven-Baked)
From mashed potatoes with red fish - bright, beautiful, and tasty! It takes only a little longer than making mash and fish, but the presentation makes it festive.
Updated : 11 February, 2026
Easy
About 30 min.
Ingredients
Main
650 grams
Potato
350 grams
Fish fillet
2 teaspoon
Olive oil
25 grams
Butter
90 grams
Hard cheese
80 milliliters
Milk
to taste
Salt
0.5 teaspoon
Basil
to taste
Herb mix
Sauce
200 milliliters
Milk
25 grams
Butter
1 tablespoon
Wheat flour
to taste
Salt
4 grams
Parsley
Table
Table of volume measurements:
- teaspoon - 5 ml
- dessert spoon - 10 ml
- tablespoon - 20 ml
- glass - 200 ml
Preparation
Step 1
How to make potato casserole with fish in the oven? Prepare the ingredients. I used salmon fillet, but you can use red or white fish (pollock, hake, tilapia). Any neutral vegetable oil can replace olive oil.
Step 2
Salt each piece of fish fillet and season with spices and herbs to taste. I used basil and herbes de Provence. For juiciness, drizzle with olive oil. Cover the fish and leave for 30 minutes so the seasonings bloom.
Step 3
Wash the potatoes well with a brush under running water and peel them. Boil the potatoes in salted water over moderate heat until tender.
Step 4
While the potatoes cook, make the milk sauce. Warm the milk slightly. Dill can be used instead of parsley.
Step 5
Melt the butter in a thick-bottomed skillet.
Step 6
Add the flour and stir. Fry the flour over low heat, stirring constantly, for 1 minute.
Step 7
Pour in the milk in small portions, whisking vigorously each time until no flour lumps remain.
Step 8
Cook the sauce over low heat, stirring, until slightly thickened, about 2 minutes. Lightly salt the sauce.
Step 9
Rinse the parsley thoroughly under cold water, pat dry, and finely chop.
Step 10
Add the herbs to the sauce, stir, and remove from heat.
Step 11
Drain the cooked potatoes. Mash them, adding butter and warm milk at the same time.
Step 12
The mashed potatoes should be smooth and lump-free.
Step 13
Grease a baking dish with a small piece of butter. Spread the mashed potatoes and smooth with a spoon. My dish was 27×17 cm (about 10.6×6.7 in).
Step 14
Divide the mashed potatoes into 4 equal sections by making grooves at least 1 cm (about 0.4 in) deep and wide.
Step 15
Fill the grooves with the milk sauce.
Step 16
Grate the cheese on a coarse grater.
Step 17
Scatter the cheese over the divided sections of mashed potatoes.
Step 18
Place a piece of fish fillet on top of the cheese on each section.
Step 19
Bake in a preheated oven at 180°C (356°F) for about 25-30 minutes, until the fish is done. Don’t overbake so the fish and cheese crust don’t dry out. If needed, cover the dish with foil.
Step 20
Serve the potato casserole with fish hot, with fresh vegetables. Enjoy!
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