- Preheat oven to 275 degrees. Season roma tomatoes with the fleur de sel, pepper, and oregano, and drizzle with olive oil. Place on a wire rack skin side up. Roast for 3 ½ hours.
- Increase oven heat to 300 degrees. On a sheet pan, place garlic, onions, and potato and drizzle with olive oil. Place in oven and bake until tender, about 30 minutes.
- Season the zucchini, eggplant and yellow squash with salt and pepper.
- Place a medium skillet over high heat and add blended oil. Heat oil until it begins to smoke, then add seasoned vegetables. Sauté until caramelized to a golden color, about 3 minutes.
- Add garlic and thyme to skillet and stir to combine.
- Remove vegetables from pan and place on a paper towel to cool slightly. Discard garlic and thyme.
- On individual plates, begin stacking the vegetables beginning with potatoes. Next, add a layer of eggplant and squash, and then finish with a layer of tomatoes.