Prepare the Vegetables:
Preheat your grill or grill pan to medium-high heat. In a large bowl, toss the zucchini, squash, bell peppers, onion slices, and cherry tomatoes with olive oil, salt, and pepper.
Grill the Vegetables:
Place the vegetables on the grill in a single layer. Cook for 3–5 minutes per side, or until grill marks appear and the vegetables are tender. Remove from the grill and set aside.
Make the Basil Vinaigrette:
In a blender or food processor, combine the basil leaves, olive oil, lemon juice, garlic, honey, salt, and pepper. Blend until smooth. Taste and adjust seasoning as needed.
Assemble the Dish:
Arrange the grilled vegetables on a serving platter. Drizzle generously with the basil vinaigrette, or serve it on the side for dipping.