Directions

1. Preheat grill to medium-high. Bring a large pot of water to a boil. Combine basil, Parmesan, walnuts, garlic, 1/4 tsp. salt, and 1/8 tsp. pepper in a food processor; pulse until finely chopped. Slowly pour 1/4 cup oil through the feed tube; continue processing until the mixture is smooth. Transfer to a medium bowl and set aside.
2. Combine portobellos, bell peppers, squash, scallions, and the remaining 2 Tbsp. oil, 1/4 tsp. salt, and 1/8 tsp. pepper in a large bowl; toss to coat.
3. Oil the grill grates (see Tip). Grill the vegetables until tender and lightly charred, 6 to 8 minutes per side. Remove from the grill and coarsely chop.
4. Cook pasta according to package directions. Add zucchini "noodles" to the pasta during the last 2 minutes of cooking. Reserve 1/2 cup pasta water before draining. Drain the pasta and zoodles and place in a large bowl.
5. Whisk 1/4 cup of the reserved pasta water into the pesto. Pour over the pasta and toss to coat, adding more reserved pasta water if needed to loosen the sauce. Add the grilled vegetables and beans; toss to coat well.