Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Dice the eggplant, zucchini, red bell pepper, and yellow onion into uniform half-inch cubes to ensure even cooking.
Place the chicken breast and the diced vegetables on the baking sheet, then drizzle with the extra virgin olive oil.
Season the chicken and vegetables with sea salt, black pepper, and dried oregano, tossing the vegetables to coat thoroughly.
Roast in the oven for 20 to 25 minutes until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly caramelized.
While the tray is roasting, mince the garlic and add it to a small saucepan with the tomato puree over medium-low heat, simmering for 5 minutes.
Once roasted, slice the chicken into thin strips and gently fold the roasted vegetables into the warm tomato sauce.
Serve the ratatouille in a shallow bowl, top with the sliced chicken, and garnish with fresh torn basil leaves.