Mussel Minestrone

Name: Mussel Minestrone
Ingredients: 50g (about 3 ½ tablespoons) unsalted butter; 1 small onion, diced; ½ a zucchini, diced; 1 carrot (about 100g), diced; ¼ of a rutabaga (about 100g), diced; 1 small leek (about 100g), diced; 2 sticks of celery, diced; 2 teaspoons medium-hot curry powder; 1 bay leaf; 150ml (about ¾ cups) dry white wine; 450ml (about 2 cups) good-quality fish stock; 500ml (about 2 ¼ cup) water; 500g (about 1 lb.) mussels, cleaned, debearded and left in a bowl of clean, cold water; 1 small bunch of parsley, chopped; 4 tablespoons Greek yogurt; 4 slices of sourdough bread, toasted; 4 teaspoons mango chutney; 100g (about 7 tablespoons) butter