Portobello Mushrooms with Garlic, Parmesan and Pine Nuts

From Steven Raichlen’s “How to Grill” book.

4 Lg. portobello mushrooms
2 large cloves garlic, cut into slivers
1 oz. Romano, Parmigiano-Reggiano or other firm cheese, cut into slivers
1 sprig fresh rosemary leaves or 2 tsp. dried rosemary
2 tbs. pine nuts
1/2 cup plus 2 tbs. balsamic vinegar
1/2 tsp. coarse salt
1/2 tsp. black pepper
1 1/3 cups extra-virgin olive oil
12 fresh basil leaves, thinly slivered

1. Trim the stems off the portobellos. Using a sharp object, make a series of holes in the portobellos in the gill side of the mushroom caps, 1/2 inch apart.  Insert garlic and cheese slivers, rosemary leaves and pine nuts in these holes.

2. Combine 1/2 cup vinegar and the salt and pepper into a nonreactive (glass, I assume) mixing bowl and whisk until the salt is dissolved. Whisk in the oil and basil. Pour some of the mixture in the bottom of a nonreactive baking dish and arrange the portobellos in it, gill side up. Swish the mushrooms around to coat the bottoms with marinade. Spoon the remaining marinade over the portobellos.  Let marinate in the fridge, covered, for as little as 30 minutes or as long as 3 hours.

3. Preheat grill to high (this always means medium on my grill).

4. When ready to cook, remove the mushroom caps from the marinade. Strain the marinade if the basil looks wilted. Whisk the remaining 2 tbs. vinegar into the marinade. Arrange the portobellos on the hot grate, gill side down. Grill for 3 minutes, then invert the portobellos and spoon on some of the reserved marinade. Continue grilling until the caps are browned and very tender, 4 to 6
minutes, rotating the caps 45 degrees after 2 minutes to create an attractive cross-hatch of grill marks. Transfer to a platter and serve at once.

The recipe also says you can try different things to insert into the shrooms like prosciutto, chorizo, lemon zest, olives, almonds, etc.

{via Casey}