Chicken in Tarragon Sauce

4 boneless, skinless chicken breast halves
1 tbsp. unsalted butter
1 tbsp. extra-virgin olive oil
Salt and freshly ground pepper, to taste
3 tbsp. chopped shallot
1 tbsp. chopped fresh tarragon
1/2 c. heavy cream
Fresh lemon juice, to taste (optional)
Chopped fresh flat-leaf parsley, for garnish

Trim any excess fat from chicken. Rinse and pat dry with paper towels. One at a time, place a chicken breast half between 2 sheets of waxed paper or plastic wrap. Using a rolling pin, flatten to an even thickness of about 1/2 inch.

In a large saute pan or fry pan over medium-high heat, melt butter with olive oil. When hot, add chicken, season with salt and pepper, and saute gently, turning once, until chicken is golden and opaque throughout and juices run clear when meat is pierced with a knife, about 3 minutes per side. Transfer chicken to a warmed plate and keep warm. Pour off any excess fat from pan and place pan over medium-low heat. Add shallot and saute, stirring, until translucent, 1 to 2 minutes. Add tarragon and cream, increase heat to medium and stir with a wooden spoon, scraping up any browned bits from the pan bottom and blending well. Cook, stirring, until bubbling and thickened slightly, 2 to 3 minutes. Season with salt and pepper and a squeeze of lemon juice. Return chicken to pan and turn each breast several times in sauce until well-coated and hot. Transfer chicken to warmed serving plate or individual plates and spoon remaining sauce over chicken. Sprinkle with parsley and serve immediately.