Heat olive oil in a pan over a medium heat
Add onion, garlic and sauté until translucent
Add red and yellow pepper and sauté until soft
Add diced tomato and cook until mushy
Add balsamic vinegar, salt, black pepper and mix well
Blend them until soft with a hand blender
Level the above sauce in a baking dish
Arrange onion, eggplant, zucchini, tomato over the sauce such that it covers the sauce
Sprinkle some olive oil, salt, basil and thyme
Pre-heat oven to 230°C
Cover the baking dish with foil and bake for 30min
Tear basil leaves, and sprinkle lemon zest
Serve hot with toasted bread or steamed rice