01 - Preheat the oven to 400°F. Lightly grease a large baking dish with a small amount of olive oil.
02 - In a small mixing bowl, whisk together the olive oil, minced garlic, lemon zest, lemon juice, dried oregano, fresh thyme leaves, salt, and black pepper until well combined.
03 - Arrange the chicken breasts in the prepared baking dish and brush generously with half of the marinade mixture, ensuring even coverage on all sides.
04 - Scatter the sliced zucchini, red bell pepper, red onion, and halved cherry tomatoes around and over the chicken. Drizzle the remaining marinade evenly across the vegetables.
05 - Bake uncovered for 25 minutes until the chicken begins to brown and the vegetables start to soften.
06 - Remove the dish from the oven and scatter the baby spinach leaves over the top. Sprinkle the crumbled feta cheese evenly across the entire dish. Return to the oven and bake for an additional 8–10 minutes, or until the chicken is cooked through to an internal temperature of 165°F and the vegetables are tender.
07 - Remove from the oven and garnish with freshly chopped basil. Serve immediately while hot.