Preheat your oven to 400°F (200°C).
Dice the eggplant, zucchini, red bell pepper, and yellow onion into uniform bite-sized pieces.
Toss the eggplant, zucchini, and bell pepper with half of the olive oil and a pinch of salt on a parchment-lined baking sheet.
Roast the vegetables for 20 minutes until tender and slightly caramelized at the edges.
While vegetables roast, season the chicken breast with the sea salt and black pepper.
Heat the remaining olive oil in a large skillet over medium-high heat and sear the chicken for 6-7 minutes per side until fully cooked, then set aside to rest.
In the same skillet, add the diced onion and sauté for 3-4 minutes until translucent.
Add the minced garlic, dried thyme, and dried oregano to the skillet, cooking for 1 minute until fragrant.
Stir in the tomato puree and the roasted vegetables, allowing the mixture to simmer on low for 5 minutes to meld the flavors.
Slice the rested chicken breast into strips.
Plate the vegetable ratatouille and top with the sliced chicken.
Garnish with freshly chopped basil before serving.