1/4 pound mushrooms, halved (if "button" size) or quartered (if larger)
1 yellow onion, peeled, stem and root ends removed, then cut into 1-inch chunks
4 tablespoons extra-virgin olive oil, divided, plus more for brushing fish
Salt and pepper, to taste
3/4 pound slender-stalked asparagus, tough end trimmed
6 (3-ounce) pieces fresh halibut
1 tablespoon red-wine vinegar
1 tablespoon balsamic vinegar
About 1/4 pound fresh, young arugula, stemmed
1/2 cup crumbled feta cheese
1/3 cup lightly toasted pine nuts

Preheat oven to 450 F.

Arrange the mushrooms and onion in a single layer in a roasting pan (measuring about 11 by 17 inches or larger). Drizzle with 2 tablespoons of the olive oil and toss to coat vegetables, then salt and pepper lightly. Place in preheated oven and roast for about 20 minutes.

Add the asparagus and toss vegetables again to coat asparagus with oil and seasoning. Return pan to oven and continue roasting for about 10 more minutes (vegetables should be tender and slightly browned).

Brush the halibut pieces with olive oil and sprinkle with freshly ground black pepper. Place fish on cooking grate of a preheated grill and cook for 7 to 8 minutes or to desired doneness (general rule of thumb is 10 minutes total cooking time per 1-inch thickness of fish), turning once halfway through cooking time.

Whisk the vinegars with remaining 2 tablespoons olive oil. Add additional salt and pepper to taste.

Remove vegetables from oven and arrange them on a large platter. Toss vinaigrette with the arugula, feta cheese and pine nuts and arrange on top of roasted vegetables. Serve immediately, along with grilled halibut and crusty artisan bread.

Makes 6 servings.