Chicken Breasts with Tarragon Cream Sauce (Phase 1)

4 boneless, skinless chicken breast halves
1 tablespoon butter ? (substitute with low-cal spread? or perhaps chicken broth?)
1 tablespoon olive oil
1/2 cup light or fat free cream
1 tablespoon Dijon mustard
2 teaspoons chopped fresh tarragon or 3/4 teaspoon dried
Salt
Pepper

Sprinkle chicken with salt and pepper. In a large skillet over medium heat, melt butter with oil. Brown chicken breasts on both sides. Reduce heat and cook, covered, for 15 minutes, or just until chicken is cooked through. Transfer chicken to a serving platter; tent with foil to keep warm.
Add cream to skillet; scraping brown bits from the sides. Stir in mustard and tarragon. Cook over medium heat, stirring constantly for about 5 minutes until sauce thickens slightly. Season to taste with salt and pepper. Pour sauce over chicken.

Ellis, would you use butter as this says or substitute something else?

Barb, I was going to put a question mark beside this, and forgot... I'd say use a low-cal margerine.

This is soooo yummy - my hubby loves it. I added mushrooms to it last night as well which was really good. Thanks!