Fish with Creamy Leek Sauce

Name: Fish with Creamy Leek Sauce
Prep time: 25 min
Yield: 4
Cuisine: Francesa
Ingredients: 3 tablespoons unsalted butter; 1/2 cups leek, only the white and light green parts, cut into 1 cm pieces.; 1/3 cups dry white wine; 1/3 cups sour cream; 2 tablespoons chives, finely chopped; 1/4 cups chicken broth; 1 tablespoon olive oil; 4 white fish fillets, like Sea Bass with its skin