Ingredients

• 1/2 cup sour cream
• 1 1/2 teaspoons all-purpose flour
• 2 medium leeks (white and pale green parts only), thinly sliced
• 2 tablespoons unsalted butter
• 2/3 cup water, divided
• 4 (6-ounce) pieces thick white-fish fillets such as pollock or Pacific cod, skinned
• 1 tablespoon chopped dill

Instructions

1. Whisk together sour cream and flour.
2. Wash leeks, then put in a large heavy skillet with butter, 1/3 cup water, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Cover with parchment, then with a lid, and simmer over medium heat, stirring once or twice, until leeks are tender, about 10 minutes.
3. Stir in sour-cream mixture and remaining 1/3 cup water.
4. Season fish with 1/4 teaspoon each of salt and pepper, then add to leeks and cook, covered with parchment and lid, until just cooked through, 8 to 10 minutes. Serve sprinkled with dill.