Step 1

Heat a heavy soup pot over medium heat and add bacon (or pancetta); cook, stirring occasionally, until browned, 4 to 6 minutes. Transfer to a paper-towel-lined plate; pour off all but 1 tablespoon of the fat in the pot.

Step 2

Add 1 tablespoon oil, 2 medium chopped onions, carrot, celery, garlic and fennel seed. Cook, stirring occasionally, until the vegetables are tender and just beginning to color, about 5 minutes. Add dry mustard and cook, stirring, for 1 minute more. Add 4 cups broth, potatoes and rutabaga and bring to a boil.

Step 3

Reduce heat to maintain a simmer, cover and cook until the vegetables are tender but still hold their shape, 15 to 20 minutes. Mash a few of the vegetables against the side of the pot with the back of a spoon and cook for 2 minutes more to slightly thicken the soup.

Step 4

Stir in cream sauce and heat until steaming but not boiling. Remove from heat; add cheese and stir until melted. Season with pepper. Serve topped with chives (or scallion greens) and the reserved bacon (or pancetta).