- 2 tablespoons fresh lemon juice
- 1 teaspoon grated lemon peel
- 1 teaspoon Dijon mustard
- 5 tablespoons olive oil
- 1/2 cup thinly sliced fresh basil
- 1/2 cup paper-thin slices red onion
- 1 1/2 pounds medium zucchini, trimmed, quartered lengthwise, then cut crosswise in half
- Combine lemon juice, lemon peel and mustard in bowl; gradually whisk in oil. Stir in basil and onion. Season with salt and pepper. Let stand at least 1 hour and up to 6 hours, stirring occasionally.
- Steam zucchini until just crisp-tender, about 5 minutes. Transfer to large bowl; cool completely. Add dressing and toss to coat. Let stand 1 hour for flavors to develop, stirring often.