2 cups loosely packed fresh basil
2 cloves garlic
2/3 cup olive oil, divided
1/2 tsp each sea salt and ground black pepper, divided
4 plum tomatoes, halved lengthwise
2 bell peppers, seeded and quartered (you can use any color)
1 eggplant, sliced into ½-inch-thick rounds
1 large zucchini, sliced on the bias into 1/2-inch-thick rounds
1 small red onion, sliced into 1/4-inch-thick rounds
Heat a grill to medium-high. In a food processor, pulse basil and garlic until finely chopped. With motor running, gradually drizzle in all but 1 tbsp oil. Season with 1/4 tsp each salt and black pepper. Set aside.
On a large rimmed baking sheet, arrange tomatoes, peppers, eggplant, zucchini and onion in a single layer. Brush with remaining 1 tbsp oil and sprinkle with remaining 1/4 tsp salt and black pepper.
Grease grill grates. Place peppers, eggplant, zucchini and onion on grill. Close lid and grill, turning once, until softened and grill-marked, 5 to 7 minutes. Place tomatoes, cut side down, on grill. Close lid and grill, turning once, until softened, about 4 minutes.
Arrange eggplant, zucchini and onion on a large serving platter. Transfer peppers and tomatoes to a cutting board. Slice peppers into strips; add to platter. Peel tomatoes and chop flesh into 1-inch pieces; add to platter. Drizzle with basil mixture.