In a medium bowl, whisk together white wine vinegar, garlic, honey, salt and pepper. While whisking, slowly pour in canola oil.
When grilling the tofu, it is a good idea to press it first to remove additional liquid, which will stop the tofu from falling apart on the grill. Lay a double sheet of paper towel on a plate, place the tofu on top, lay additional paper towel over top and press gently. Replace paper towels with a fresh set, lay a plate on top and let rest for 20 minutes. It’s now ready to use.
- Lay the tofu in a wide, shallow container and pour in half of the marinade, turning the tofu to coat. Let rest for at least 30 minutes and up to 1 hour.
- Spray grill with cooking spray and preheat to medium-high heat.
- Place the mushrooms, red bell pepper and summer squash in a large bowl. Toss with remaining marinade.
- Remove tofu from marinade and gently place tofu and vegetables on grill. Depending on the size of the grill, this may need to be done in two batches. Cook until tofu has dark grill marks are vegetables are tender, about 4 to 5 minutes per side for the tofu and red peppers, and 3 to 4 minutes per side for the mushrooms and summer squash.
- Lay one portobello mushroom on each of four plates, top with one slice of tofu, 1 teaspoon basil pesto, some of the mint and one piece of red bell pepper. Then top with tofu, 1 teaspoon pesto, summer squash and remaining pesto. Garnish with remaining mint. Serve.