Prepare Italian Dressing according to packaged instructions.
Place a grill pan over medium-high heat.
Brush the vegetables with 1/4 cup of the Italian Dressing to coat lightly.
Working in batches, grill the vegetables until tender and lightly charred all over; about 8 to 10 minutes for the bell peppers; 7 minutes for the yellow squash, zucchini, eggplant, and mushrooms; 4 minutes for the asparagus.
Arrange the vegetables on a platter.
Drizzle Italian Dressing over the vegetables.
Serve the vegetables warm or at room temperature.
Tip: The key to getting those great grill marks is to not shift the vegetables too frequently once they've been placed on the hot grill.