Seafood Pie With a Caper Rosti Topping

Name: Seafood Pie With a Caper Rosti Topping
Ingredients: 650 g whit fish fillets, chopped coarsely; 250 g medium cooked prawns, shelled, deveined; 30 g butter; 260 ml sour cream; 2 tablespoons dry white wine; 1 tablespoon lemon juice; 1 teaspoon fish stock granules; 1 teaspoon vegetable stock powder; 1⁄4 cup fresh dill, chopped finely; 1⁄2 cup frozen peas; Caper Rosti Topping; 500 g potatoes, peeled and grated coarsely; 2 tablespoons baby capers; 30 g butter, melted