Perch Strudel with Chestnuts and Cabbage
For the dough, mix flour, egg, oil and water and knead into a smooth dough. Wrap in plastic wrap and let rest for 1 hour.
For the filling, rinse, peel and cook potatoes until tender in salted water. Blanch cabbage leaves in salt water, rinse under cold water and pat dry. Peel shallots and finely chop. Heat 1 tablespoon of butter and cook shallots until golden. Deglaze with vinegar, pour in white wine add bay leaf and let liquid reduce by half. Pour resulting sauce through a fine sieve and set aside.
Divide perch in 4 portions and season with salt and pepper. Heat oil and fry fish on each side briefly. Finely chop 1/3 of chestnuts. Melt 1 tablespoonof butter. Roll out pastry thinly on a lightly floured surface to 20 cm x 20 cm (approximately 8 x 8 inches) and cut into 4 squares. Brush squares with melted butter and top with chopped chestnuts, cabbage leaves and perch. Fold each square into a packet and brush outsides with butter.
Place packets on a lined baking sheet and bake in preheated oven at 180°C (approximately 350°F) for approximately 10–12 minutes. Press remaining chestnuts and boiled potatoes through a ricer. Heat milk and add in potato mixture and rest of butter. Season with salt and a pinch of nutmeg, then sprinkle with parsley.
Heat sauce, add cold butter in small pieces to bind and stir with a whisk, but do not allow to boil. Season sauce with salt and pepper and serve over strudel parcels.