A dry, full-bodied Grüner Veltliner stands up well to the salmon in this dish and complements herbs like dill and parsley.
Preheat oven to 200°C/400°F. Peel and thinly slice potatoes. Slice green onion crosswise into rings. Finely mince dill and parsley. Cut carrots into bite-sized pieces. Mince garlic. Remove skin from cod and salmon and cut into bite-sized pieces. Parboil the potatoes and carrots in a pot of boiling water for approx. 5 min., then drain.
Melt butter in a large saucepan over medium heat. Add flour and stir constantly to form a roux. Deglaze with white wine.
Add mustard, milk, lemon juice, and minced garlic to saucepan. Season to taste with salt, pepper, and sugar. Add dill, parsley, and green onions. Stir well and bring to a boil for approx. 2 – 3 min. Remove from heat and set aside.
Add all ingredients to baking dish, season with salt and pepper, and place in preheated oven 200°C/400°F for approx. 10 – 15 min. Enjoy!