How to Make It
Preheat a grill pan over medium-high. Toss together eggplant, zucchini, squash, mushrooms, onion, and 3 tablespoons of the oil in a large bowl until coated. Spray a grill pan with cooking spray. Grill vegetables, in batches, in a single layer until charred and tender, flipping once, about 10 minutes for the eggplant and mushrooms and 8 minutes for the zucchini, squash, and onion. Transfer vegetables to a platter, add tomatoes, and season all evenly with 1/2 teaspoon of the salt.
Stir together vinegar, parsley, tarragon, pepper, and remaining 1 tablespoon olive oil and 1/8 teaspoon salt in a small bowl. Stack vegetables on serving plates, alternating vegetables until you have stacks of about 8 vegetables each. Top with goat cheese, and drizzle with vinaigrette.