A main course and a salad in one: polenta, arugula, and portobellos with a warm balsamic sauce. The trick to grilling polenta is to know when to flip it. Wait until the entire piece can be lifted off the grates cleanly with a metal spatula. This way, the crisp surface won't stick to the grill.
Martha Stewart Living, October 2007
Yield Serves 4
6 portobello mushrooms (about 1 pound), stems and caps separated, halved if very large
1/4 cup plus 1 tablespoon extra-virgin olive oil, plus more for brushing
1/2 cup homemade or low-sodium store-bought chicken or vegetable stock
12 pieces set polenta (about 1/2 batch) Basic Polenta (Soft or Set) (http://www.wholeliving.com/142028/basic-polenta-soft-or-set), cut into 1-inch-thick rectangles or triangles
2 cups arugula (2 ounces)
8 ounces Parmigiano-Reggiano, shaved
Toss portobellos with garlic, herbs, salt, pepper, vinegar, and 1/4 cup oil in a large bowl. Let stand at room temperature, tossing occasionally, for 1 hour.
Transfer portobellos to a plate. Pour marinade into a small saucepan, and bring to a boil. Reduce heat, and simmer 1 minute. Add stock. Raise heat, and bring to a boil. Reduce heat, and simmer until reduced by half, about 10 minutes. Stir in remaining tablespoon oil, and remove from heat.
Preheat grill to medium-high. (If you are using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for just 3 to 4 seconds.) Lightly brush top and bottom of polenta with oil, and place in center of grill. Cook, flipping once, until polenta is marked, crisp, and no longer sticks to grill, 6 to 8 minutes per side. Meanwhile, place portobellos on cooler part of grill, and cook, turning frequently to avoid burning, until tender, about 10 minutes.
Place arugula on a platter, and arrange polenta and portobellos on top. Drizzle about half the sauce over portobellos. Top with Parmigiano-Reggiano. Serve immediately with extra sauce on the side.