Wash all vegetables thoroughly and prepare them as per ingredient specifications.
Heat a large pan over medium heat with olive oil. Add onions, garlic cloves
sauté until softened without browning (about 3-5 minutes).
Add the diced tomatoes along with salt to taste and simmer for about 10 minutes.
Meanwhile in a separate pan grill or roast slices of eggplant, zucchini, and yellow squash until they have nice char marks (about 5-7 minutes each). Let them cool slightly before adding into the main pot to avoid overcooking vegetables. Mix well with tomato sauce.
Stir in thyme leaves for added flavor
Serve hot, garnished with a drizzle of olive oil and additional fresh herbs if desired.