- 1/3 cup walnuts
- 1 garlic clove, finely grated
- 2 tablespoons fresh lemon juice
- 5 tablespoons olive oil, divided
- Kosher salt
- Freshly ground black pepper
- 2 large leeks, white and pale-green parts only, halved lengthwise with some root attached
- 2 large zucchini (about 1 pound), halved lengthwise
- 1/2 cup (lightly packed) fresh flat-leaf parsley leaves with tender stems
- Prepare grill for medium-high heat. Toast walnuts in a dry small skillet over medium heat, tossing often, until fragrant, about 5 minutes. Chop very coarsely. Toss warm walnuts with garlic, lemon juice, and 3 tablespoons oil in a large bowl; season with salt and pepper.
- Brush leeks and zucchini with remaining 2 tablespoons oil; season with salt and pepper. Grill vegetables, turning often, until tender and charred in spots, 5-8 minutes for leeks, 8-10 minutes for zucchini.
- Transfer vegetables to a cutting board. Trim roots from leeks and cut leeks and zucchini into bite-size pieces. Add vegetables and parsley to bowl with walnuts and toss to combine; season vegetables with salt, pepper, and more lemon juice, if desired.