Step 1

Preheat oven to 425F. Arrange eggplant and zucchini on a non-stick baking sheet in a single layer and sprinkle the chopped onion over them. Sprinkle with salt and pepper. Put the head of garlic in a corner of the baking sheet, and place in the oven. Stir after 15 minutes and add the bell pepper, mushrooms, and tomatoes. Cook until mushrooms have softened and tomatoes are beginning to collapse, about 10 more minutes. Remove from oven, reserve the head of garlic, and place the other vegetables in a very large serving bowl. (If your oven is small, see the Notes below.)

Step 2

While the vegetables are cooking, cook the pasta according to package directions. Drain and add pasta to vegetables, along with chickpeas and olives, if desired.

Step 3

Make the dressing: Place the basil in a food processor. Squeeze out 4-6 cloves of roasted garlic (or however many you like) and add it to the food processor, along with walnuts and nutritional yeast, if you’re using them. Pulse 6-8 times to chop the walnuts. Add the vinaigrette and process until smooth.

Step 4

Add dressing to pasta and vegetables, stir well, and season to taste with salt and pepper. Serve at warm, at room temperature, or chilled.