Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Cut the chicken breast, eggplant, zucchini, and red bell pepper into uniform 1-inch cubes to ensure even cooking.
In a large mixing bowl, whisk together the olive oil, minced garlic, lemon zest, dried oregano, sea salt, and black pepper.
Add the chicken and chopped vegetables to the bowl, tossing thoroughly until every piece is glistening with the herb-infused oil.
Spread the mixture onto the prepared baking sheet in a single layer, making sure not to overcrowd the pan so the vegetables roast rather than steam.
Roast in the oven for 20 to 25 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized.
While the tray is roasting, gently warm the tomato puree in a small saucepan over low heat.
Transfer the roasted chicken and vegetables to a serving bowl and toss with the warm tomato puree before serving hot.