Perch with Vegetables En Papillote
Peel carrots and parsnips, halve lengthwise and chop. Heat butter with olive oil in a pan and saute vegetables for about 10 minutes, stirring occasionally. Season with salt and pepper. Rinse fish, pat dry and season with salt and pepper.
Oil 4 sheets of baking paper on the work surface and spread with vegetables. Place fish fillets in the middle and sprinkle with tarragon. Fold in paper, sealing tightly. Bake in preheated oven at 140°C (approximately 275°F) for about 25-30 minutes. Remove from the oven and unfold carefully. Serve.