Balsamic Glaze Mushrooms

This is another recipe out of Nancy Silverton's Mozza at Home cookbook, and it is equal parts delicious and easy.

1 cup balsamic vinegar
1 shallot, diced
1/4 cup olive oil
2 lbs. mixed mushrooms
salt to taste
1/4 c. fresh tarragon leaves

Heat 2 tablespoons of olive oil in a large saute pan.  Cook the mushrooms, cap side down, season with salt along the way.  Cook until browned, about 10 minutes.  Do it in two batches if your pan is not big enough.  Pout about 1/3 c. vinegar  in and  cook until the mushrooms have absorbed the vinegar, then add more, taste, and add shallots, toss some more, and add more vinegar to taste.  Garnish with tarragon leaves, and salt to taste.