Step 1

Place bulgur and 1/2 teaspoon salt in a large bowl. Add boiling water and stir. Cover with plastic wrap and let soak until tender and liquid has been absorbed, about 30 minutes.

Step 2

Meanwhile, preheat grill to medium-high. Place a fine-mesh nonstick grill topper on the grill to heat.

Step 3

Place zucchini, onions, portobellos and tomatoes in a single layer on a baking sheet. Brush both sides with 1 tablespoon oil and sprinkle with remaining 1/4 teaspoon salt and pepper. Working in batches, grill the vegetables until tender, turning once or twice. Allow 8 to 10 minutes for zucchini and onions, 6 to 8 minutes for mushrooms, and 2 to 3 minutes for tomatoes.

Step 4

Toast walnuts in a small dry skillet over medium-low heat, stirring constantly, until fragrant, 2 to 3 minutes. When the vegetables are cool enough to handle, coarsely chop the zucchini, onions and mushrooms. Cut the tomatoes in half.

Step 5

When the bulgur is tender, add the remaining 2 tablespoons oil, lemon juice, parsley and mint; toss to mix. Add the vegetables and toss. Sprinkle with walnuts.