Heat 1 tbsp extra virgin olive oil in a large saute pan on medium-high. Add the onions, season with salt, and cook until translucent, with edges just beginning to turn golden brown. Add garlic, and cook a minute more until soft.
Add eggplant, bell pepper, tomatoes, and zucchini. Season with salt and pepper, and stir to combine.
Add thyme sprigs and bay leaf, turn heat to medium-low, and let simmer until vegetables have begun to soften, about 10 minutes. When vegetables have reached desired consistency, remove from heat and remove thyme sprigs.
Garnish with chopped basil, and season once more to taste.