That recipe looks very similar to this one, which I thought I had already posted here, but I guess I haven't. This is what my daughter requests every year for her birthday. It's very easy to scale it to make more or fewer servings.

Sauteed Chicken Breasts with Mushroom Sauce

Serves 6

Amount Measure Ingredient -- Preparation Method
-------- ------------ --------------------------------
6 tablespoons flour
3/4 teaspoon ea salt and pepper
6 boned and skinned chicken breasts
6 teaspoons vegetable oil
24 ounces fresh mushrooms -- sliced
1 cup onion -- finely chopped
1 1/2 cups chicken broth
6 tablespoons balsamic vinegar
6 cloves garlic -- sliced
4 1/2 teaspoons fresh thyme
3 tablespoons butter

Combine flour, salt and pepper in a ziplock bag. Flatten chicken to an even thickness and shake in flour mixture. Heat oil in nonstick skillet over medium heat. Add chicken and saute three minutes on each side. Remove to platter and cover to keep warm. Using same skillet over medium heat, combine mushrooms and onion and cook 5 minutes or until golden. Add broth, vinegar, garlic & thyme. Bring to a simmer and cook 4 minutes. Remove from heat; stir in butter. Spoon sauce over chicken and serve.