3 tablespoons butter
2 leeks, thinly sliced (white and pale green parts only)
1 medium onion, thinly sliced
5 turnips (about 2 1/2 pounds), peeled, cut into 1/2-inch-thick slices
1 medium russet potato, peeled, cut into 1/2-inch-thick slices
5 cups (or more) canned low-salt chicken broth
1 3/4 cups milk
1/4 cup whipping cream
Pinch of ground nutmeg
2 carrots, cut into matchstick-size strips
1 turnip, peeled, cut into matchstick-size strips
2 tablespoons chopped fresh dill
Melt butter in heavy large Dutch oven over medium heat. Add leeks and onion and sauté until onion is translucent, about 12 minutes. Add 5 sliced turnips and potato and sauté 2 minutes. Add 5 cups broth. Bring to boil. Reduce heat to medium-low and simmer until vegetables are very tender, about 30 minutes.
Puree soup in blender in batches until very smooth. Return to Dutch oven. Add milk and cream. Bring to simmer. Season to taste with nutmeg, salt and pepper. (Can be prepared 1 day ahead. Cover and refrigerate.)
Cook carrot and turnip strips in pot of boiling salted water until just crisp-tender, about 2 minutes. Drain.
Bring soup to simmer, thinning with more broth if necessary. Ladle into bowls. Garnish with carrot strips, turnip strips and chopped fresh dill.