-12 inch x 36 cm, frozen or -homemade See other recipes for Spinach Mousse and Salmon Mousse, and Beurre Blanc. Remove the fish filets from the backbone, keeping the head and tail intact. Roll the pastry into a rectangle and put the head, tail and bottom filet on the pastry. Spread the filet with some salmon mousse and then some spinach mousse. Cover with the top filet. Paint the pastry with melted butter and trim it down to the shape of a fish. Fold over half of the pastry and paint it with melted butter again. Fold over the other side and smooth into a fish silhouette. Paint the pastry again and decorate it with pastry scraps cut into the shapes of scales and fins. Paint the entire pastry with additions with butter and put it all on a lightly buttered baking sheet. Preheat your oven to 180ºC . Put the pastry in the oven and bake until golden, about 40 minutes. Serve with the beurre blanc.