1/2 ounce dried porcini mushrooms, soaked in 1 cup hot water for 20 minutes
3 tablespoons plus 1 teaspoon extra-virgin olive oil
1 small red onion (about 4 ounces), finely chopped
4 large cloves garlic, finely chopped
1 pound white button mushrooms, thinly sliced
1/2 cup dry red wine
1-1/2 tablespoons tomato paste
1/2 teaspoon dried rosemary
Salt and freshly ground black pepper, to taste
3 cups water
3 cups vegetable broth, preferably homemade or low-sodium canned
2 cups polenta (coarse-ground yellow cornmeal)
2 cups favorite tomato-based pasta sauce, homemade or prepared, heated
6 small sprigs fresh rosemary or fresh flat-leaf parsley