Prep the vegetables by dicing the eggplant, zucchini, red bell pepper, and yellow onion into uniform half-inch cubes.
Season the chicken breast evenly with a pinch of sea salt and black pepper.
Heat half of the olive oil in a large skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden and cooked through, then set aside to rest.
In the same skillet, add the remaining olive oil and sauté the onions and minced garlic until translucent and aromatic.
Add the eggplant, zucchini, and bell peppers to the skillet, cooking for 5-7 minutes until they begin to soften and caramelize slightly.
Stir in the crushed tomatoes, herbes de Provence, and the remaining salt and pepper, then reduce the heat to low.
Simmer the vegetable mixture uncovered for 10 minutes, allowing the sauce to thicken and the flavors to meld together.
Slice the rested chicken breast into strips and serve it over the warm ratatouille, garnished with fresh torn basil leaves.