Bring large pot of lightly salted water to boil. Blanch the turnips for 3 minute.
Drain and rinse with cold water. Lightly towel dry the turnips.
Toss turnips, onions, leeks, garlic and thyme in oil in a large bowl. Spread on a baking sheet or dish in a single layer. Roast in preheated oven for approximately 1 hour, stirring and turning every 15 minute or so until browned evenly.
Place roasted vegetables in a soup pot. Add 3/4 cup of water to pan vegetables were roasted in, scrape bits and juices and add to soup pot.
Add the stock, milk, cream and salt to pot. Bring almost to boil and partially cover. Reduce heat to simmer an cook for about 30 min or until turnips are quite tender. In a blender, puree the soup in batches.
Strain through food mill or strainer to create creamy fine consistency.
Serve with Honey Cream.
Honey Cream: Mix ingredients from above together well.