Mushroom and Root Vegetable Potpie

2 cups vegetable or fat-skimmed chicken broth

1 pound fresh mushrooms such as common, chanterelle, oyster , pompon, porcini, portabella, and shiitake (1 to 4 kinds)

1 tablespoon butter or margarine

1/2 cup chopped shallot s

1/2 teaspoon dried thyme

1/4 teaspoon dried rubbed sage

1 head fennel (about 4 in. wide)

1 1/2 pounds red thin-skinned potato es (1 to 1 1/2 in. wide), scrubbed and cut in half

3 turnip s (2 1/2 to 3 in. wide), rinsed, peeled, and cut into eighths

1/2 cup dry white wine

1 1/2 tablespoons cornstarch

1/4 cup whipping cream

1 cup chopped spinach

Salt and pepper