- 2 tablespoons red wine vinegar
- 2 teaspoons Dijon mustard
- 9 tablespoons extra-virgin olive oil, divided, plus more for brushing
- 1/2 cup crumbled blue cheese (such as Maytag; about 2 ounces)
- 2 medium zucchini, halved lengthwise
- 2 bell peppers (preferably in assorted colors), seeded, quartered lengthwise
- 1 pound red-skinned potatoes, scrubbed, cut into 1/3-inch-thick slices
- 1 fennel bulb, trimmed, cut through core into 8 wedges
- 8 fresh shiitake mushrooms, stemmed
- 10 baby beets (about 1 1/2 inches in diameter), trimmed, scrubbed, halved crosswise
- 1 large red onion, cut into 1/3-inch-thick slices
- 1 5-ounce package mixed baby greens
Whisk vinegar, Dijon mustard, and 5 tablespoons oil in small bowl. Stir in cheese. Season dressing with salt and generous amount of pepper.
Prepare barbecue (medium-high heat); brush grill with oil. Place all vegetables except beets, onion, and baby greens in large bowl; drizzle with remaining 4 tablespoons oil and toss to coat. Transfer to large rimmed baking sheet. Place beets in same bowl; toss to coat with any remaining oil in bowl and transfer to baking sheet. Sprinkle vegetables with salt and pepper. Brush onion slices with oil; sprinkle with salt and pepper. Grill vegetables until slightly charred and tender, about 12 minutes for beets, potatoes, and fennel, turning occasionally, and about 4 minutes per side for zucchini, peppers, onion slices, and mushrooms.
Mound greens in center of 4 plates. Scatter onion slices over greens. Arrange vegetables around greens. Drizzle dressing over and serve.