Whisk together the ½ cup olive oil, 4 cloves garlic minced, 2 tbsp fresh lemon juice, 1 tbsp balsamic vinegar, 1 tsp dried oregano, 1 tsp dried thyme, 1 tsp kosher salt, and ½ tsp black pepper in a small mixing bowl until well combined. Set the marinade aside.

Prepare all vegetables: slice the 2 medium zucchini sliced lengthwise into 1/4-inch planks and 1 medium yellow squash sliced lengthwise into 1/4-inch planks lengthwise into 1/4-inch planks, quarter the 2 red bell peppers seeded, cut the red onion into 1/2-inch rounds (use toothpicks to keep the rings together), trim the 1 lb asparagus tough ends, halve any large mushrooms, and cut the 2 ears of corn husked into thirds.

Place all the prepared vegetables in a large mixing bowl. Pour about 3/4 of the marinade over the vegetables and toss well to coat every piece. Reserve the remaining marinade for basting. Let the vegetables marinate at room temperature for at least 10 minutes (or up to 30 minutes for deeper flavor).

Preheat your grill to medium-high heat (about 400–450°F). Clean and oil the grates well to prevent sticking.

Grill the vegetables in batches, starting with the ones that take longest: 2 ears of corn husked and red onion first (10–12 minutes, turning every few minutes), then 2 red bell peppers seeded and mushrooms (8–10 minutes), and finally 2 medium zucchini sliced lengthwise into 1/4-inch planks, 1 medium yellow squash sliced lengthwise into 1/4-inch planks, and 1 lb asparagus tough ends (4–6 minutes). Use a grill for the 1 lb asparagus tough ends and any smaller pieces.

While grilling, brush each batch with the reserved marinade once after flipping. You're looking for visible grill marks and tender-but-not-mushy texture. Remove each vegetable to a large platter as it finishes.

Arrange the grilled vegetables on a serving platters (Large) in an appealing, colorful layout. Scatter fresh fresh parsley roughly chopped and torn 1 tbsp fresh basil torn over the top. Crumble 1 oz feta cheese over the platter if using. Serve with 1 medium lemon cut into wedges for serving wedges on the side for squeezing over.