Preheat your oven to 400°F (200°C).
Dice the eggplant, zucchini, and red bell pepper into uniform 1-inch cubes.
Place the cubed vegetables on a large baking sheet and toss with 1 teaspoon of olive oil and the sea salt.
Roast the vegetables for 20-25 minutes, tossing halfway through, until they are tender and slightly caramelized.
While the vegetables roast, season the chicken breast evenly with the dried oregano and black pepper.
Heat the remaining 1 teaspoon of olive oil in a large non-stick skillet over medium-high heat.
Sear the chicken breast for approximately 6-7 minutes per side, or until the internal temperature reaches 165°F.
Remove the chicken from the skillet and let it rest on a cutting board for 5 minutes before slicing.
In the same skillet, add the diced yellow onion and sauté for 3-4 minutes until translucent.
Add the minced garlic and cook for another 60 seconds until fragrant.
Stir in the tomato puree and simmer the sauce on low heat for 5 minutes.
Gently fold the roasted vegetables into the tomato sauce until well combined.
Plate the vegetable ratatouille and top with the sliced chicken breast and fresh basil.