Creamy Root Vegetable Soup

Name: Creamy Root Vegetable Soup
Ingredients: 5 Tbsp. unsalted butter, divided; 1 cup thinly sliced leek (from 1 leek); 2 garlic cloves, minced (about 1 1/2 tsp.); 1 lb. rutabaga, peeled and coarsely chopped (2 1/2 cups); 1 lb. sweet potatoes, peeled and coarsely chopped (3 1/2 cups); 12 oz. parsnips, peeled and coarsely chopped (2 1/2 cups); 2 dried bay leaves; 4 cups lower-sodium vegetable broth; 1/2 tsp. black pepper; 2 1/4 tsp. kosher salt, divided; 1/2 cup crème fraîche; 3/4 tsp. ground coriander; 1/4 cup pecans, chopped; 1 Tbsp. chopped fresh sage, plus more sage leaves for garnish; 1 cup heavy whipping cream