Defrost the pangasius fillets. Drizzle with lemon juice, salt and pepper. Prepare the leaf spinach according to the instructions on the package, season with garlic, salt and pepper. Peel the potatoes, cut into thin slices and cook in salted water for about 10 minutes.
Brush a baking dish with olive oil and place the pangasius fillets in it. Spread the spinach on top and cover with the potato slices. Salt, pepper and drizzle with olive oil.
Bake in the oven at 180 ° C (fan oven) for 30 minutes. Crumble the feta cheese and spread it on the potatoes. Continue baking until everything is nice and brown.