2 teaspoons extra-virgin olive oil
This salad is best served as soon as it is made.
Lightly coat the zucchini, squash, and asparagus with oil and sprinkle with salt and pepper. Grill the zucchini and squash for about 3 minutes on each side, and the asparagus for about 2 minutes total, or until they are slightly charred and cooked throughbut still crisp-tender. Transfer the vegetables to a cutting board.
Cut the asparagus spears in half lengthwise then crosswise, and cut the zucchini and squash on the bias into large bite-size pieces.
In a medium bowl, whisk half of the diced avocado with the balsamic vinegar, breaking up the avocado lightly to create a creamy texture. Slowly drizzle in the olive oil while whisking to blend. Season to taste with salt and pepper.
Mound the salad on plates or a platter and serve immediately with any remaining dressing on the side.