Developing the best pasta salad recipe was tricky: While some acidity was clearly needed to brighten the flavor of the salad, too much caused the pasta to soften and the dulled vegetables, both in flavor and appearance. We liked lemon juice for contributing a nice bright flavor that was neither puckery nor sour. When we turned our attention to the vegetables, we discovered that, as we suspected, grilling and roasting added more flavor to most vegetables (broccoli and cauliflower being the exceptions) than blanching.
Technique tip: Pasta salad can be refrigerated for up to 24 hours; return to room temperature before serving.
Swap option: The eggplant can be broiled until golden brown if you prefer not to grill it.
For a charcoal grill: Open bottom vent completely. Light large chimney starter filled with charcoal briquettes (6 quarts). When top coals are partially covered with ash, pour evenly over grill. Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.
For a gas grill: Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Leave all burners on high (adjust burners as needed to maintain grill temperature of 350 F).1.
Clean and oil cooking grate. Lightly brush eggplant with extra oil and season with salt and pepper. Cook until dark grill marks appear, about 10 minutes, flipping eggplant halfway through cooking. Let cool completely, then cut into bite-size pieces.2.
Meanwhile, bring 4 quarts water to boil in large pot. Whisk garlic, lemon zest and juice, pepper flakes and 3/4 teaspoon salt together in large bowl. Whisk in oil in slow, steady stream until smooth.3.
Add pasta and 1 tablespoon salt to boiling water and cook, stirring often, until al dente. Drain pasta. Re-whisk dressing and add tomatoes, basil, eggplant and pasta to bowl; toss to mix thoroughly. Let salad cool completely. Season with salt to taste and serve.