Preheat the oven to 425°F.

Finely chop the shallot. Rinse the leek well and cut into fine pieces. Peel the potatoes and cut them into even pieces so they cook evenly.

Melt a knob of butter in a saucepan and sweat the chopped shallot over low heat until translucent and soft. Deglaze with fish stock and white wine and let the mixture reduce. Strain the mixture and return the strained liquid to the pan. Bring it gently back to a simmer and add the cream. Heat carefully without letting it boil. Remove the pan from the heat and whisk in cold butter cubes until the sauce becomes slightly thickened and glossy. Season with salt and pepper.

Cook the potato pieces in salted water until tender. Drain and let them steam dry briefly. Meanwhile, gently cook the leek in butter until completely soft. Season with salt and pepper. Mash the potatoes with a splash of warm milk and butter into a smooth mash and fold in the stewed leek.

Purée about the basil leaves with a splash of sunflower oil to make a green oil. Finely chop the remaining basil leaves. Mix the basil oil and the chopped leaves into the ricotta and season with pepper and salt. Divide this mixture evenly over the filo sheets and carefully roll them up into little rolls. Brush the rolls with melted butter and place them on a baking sheet lined with parchment paper. Bake the filo rolls for about 10 minutes in the preheated oven until golden brown and crisp.

Rinse the cod and pat it thoroughly dry with kitchen paper. Heat enough butter in a large nonstick pan over medium heat.

Fry the cod over medium heat in the butter. Shake the pan regularly so the butter foams, and turn the fillets once the edges begin to turn white. Let them cook briefly on the second side, then reduce the heat and let the fish cook gently until just done. Work quickly and avoid overcooking so the fish stays juicy. Season with salt and pepper.

Place a spoonful of leek mash on each plate, then top with the cod and a filo roll. Spoon the warm white wine sauce over it or serve it on the side. Garnish with the remaining basil leaves and the shrimp. Enjoy!