Set your mandoline slicer to ¼" thick and thinly slice all your vegetables. Set aside.
Evenly spread marinara sauce over the bottom of the baking dish. Top with minced garlic, red pepper flakes, 2 teaspoon of fresh thyme, salt, and pepper.
Stack vegetables in a pattern and lay them in the baking dish. This can be done either in a spiral (as in the photos) or in rows if using a rectangular baking dish.
Drizzle with olive oil and sprinkle remaining thyme and pepper flakes over the top.
Cover with tin foil and bake for 50-55 minutes until vegetables are tender and the marinara sauce is bubbling up from underneath.
Remove from the oven and let cool 10 minutes before serving.
Notes
Serving and Storing - Serve with some crusty artisan bread, and a kale Caesar Salad. Store leftovers in an airtight container in the refrigerator for 2 days. Gently reheat in the oven or microwave.Recipe Tips - When picking out your veggies, try and find vegetables that all have a similar width. That means look for skinny eggplants and fat zucchinis and summer squash. This both affect the appearance of the dish as well as baking quality.