Preheat oven to 400° F
Wash vegetables well. Cut zucchini, yellow squash, red bell pepper, carrots, tomatoes, potatoes and red onions into 1-1 1/2 inch pieces as evenly as possible so that they cook evenly. Peel garlic cloves and leave whole. Add vegetables and garlic cloves to a large mixing bowl.
Finely chop fresh parsley and add to vegetable mixture. Season with salt and pepper to taste.
Pour extra virgin olive oil over vegetable mixture. Use hands to cover all vegetables well with olive oil.
Pour vegetables into a large baking pan and spread out evenly.
Add 1 tablespoon of tomato paste to 3/4 cup of water and mix well to break down the tomato paste. Pour into the corner of the pan so that the water-tomato mixture fills the pan but not directly over the vegetable mixture.
Add pan to preheated oven and cook for 45-60 minutes depending on how done you prefer your vegetables. Turn vegetables every 15-20 minutes so that they cook evenly. Add additional water if needed.