STEP 1: Preheat the oven to 400 degrees. Finely dice the onion and mince the garlic. Sauté onions in a skillet with olive oil until softened (roughy 5 minutes) then add the garlic until fragrant (about 1-2 minutes).
STEP 2: While the onion and garlic are sauteing, thinly slice the rest of the vegetables. Slice them into the same shape. I used a mandolin but you could also use a food processor or by hand as well(just try to get them to be as close to the same thickness as possible)
STEP 3: Spray the inside of an 8×8 square or round baking dish with non-stick spray. Spread the softened onion and garlic in the bottom of the dish. Place the thinly sliced vegetables in the baking dish vertically, in an alternating pattern. Sprinkle generously with salt, pepper,thyme, and rosemary.
STEP 4: Cover the dish with foil and bake for 30 minutes. Remove the foil, top with cheese and bake for another 15-20 minutes or until the cheese is golden brown.