Balsamic Roasted Vegetables

2 tablespoons balsamic vinegar

1 teaspoon Dijon mustard

1/2 cup extra-virgin olive oil

3 garlic cloves, pressed

2 teaspoons finely chopped fresh thyme

1 teaspoon finely chopped fresh basil

2 large red onions, halved, thinly sliced

1 yellow bell pepper, cut into 1/2-inch-wide strips

1 red bell pepper, cut into 1/2-inch-wide strips

1 orange bell pepper, cut into 1/2-inch-wide strips

1 1-pound eggplant, quartered lengthwise, cut crosswise into 1/2-inch slices

1/2 pound yellow squash (about 2 medium), cut into 1/3-inch-thick rounds

1/2 pound zucchini (about 2 medium), cut into 1/3-inch-thick rounds

Coarse kosher salt

Whisk vinegar and mustard in medium bowl. Gradually whisk in oil. Stir in garlic, thyme, and basil. Season to taste with salt and pepper. DO AHEAD: Dressing can be made 1 day ahead. Cover and chill.

Preheat oven to 450°F. Toss onions and next 6 ingredients in large bowl; sprinkle with coarse salt and pepper. Add dressing; toss to coat. Divide between 2 large rimmed baking sheets. Roast until vegetables are tender and slightly brown around edges, about 35 minutes.