Creamy Smoked Salmon Chowder

Name: Creamy Smoked Salmon Chowder
Ingredients: 2 tablespoons butter; 2 tablespoons light olive oil; 3 medium leeks; 2 cloves garlic (minced); 2 stalks celery (diced ); 2 medium carrots (coarsely grated); 2 medium Yukon Gold potatoes ((about 16 ounces) peeled & cubed 1/2); 1 medium Russet potato (peeled & cubed 1/2); 1 medium white-fleshed sweet potato (peeled & cubed 1/2); 1 cup clam juice; 2 cups mild vegetable stock (or chicken stock); 2 tablespoons tomato paste; 3/4 cup white wine (I use a Reisling); 2 cups water; 1/2 teaspoon paprika; 1/2 teaspoon salt; 1/2 teaspoon pepper; 1 teaspoon fresh lemon juice; 1/4-1/2 teaspoon hot sauce; 8 ounces hot-smoked salmon (divided); 1 cup heavy cream; 1 large sprig fresh tarragon