Baked Chicken and Mushrooms

I am always looking for new recipes.
In the Autumn 2007 Food and Drink magazine put out by the Liquor Control Board, found a combo I love,Portobello mushrooms and chicken.
Best of all I had everything in the cupboard.
Lots of flavour in this dish and prep time short, good for busy days.
Chicken and Mushrooms;
1/4 cup olive oil
2 TBSP. Balsamic vinegar
1 tsp. chopped garlic ( I used 2 cloves)
1 TBSP.chopped fresh sage leaves or 1/2 tsp. dried sage( used dried)
1 TBSP. Dijon mustard
4 boneless skinless chicken breasts
4 portobello mushrooms , stems removed
Salt and pepper
1 bunch watercress , stems trimmed( romaine lettuce used)
2 tsp lemon juice
2 TBSP. chopped mint ( used parsley)

Combine oil, vinegar, garlic, sage, mustard and lemon juice in large bowl.
Add chicken and mushrooms, toss to coat. Marinate for 30 minutes( marinated mine for 1 hour). Season with salt and pepper.
Heat oven to 400F.
Thickly slice mushrooms and re- assemble into casserole, lay 1 chicken breast on top of each sliced mushroom.
Spread remaining marinade on top of chicken.
Bake for 25 minutes or until juices run clear.
Place watercress(I used romaine salad greens)on serving dish sprinkle with mint ( I used Parsley).
Drizzle with any pan juices.

This was a good dinner and one I will do again.