Wash and slice any vegetables you would like to roast, totaling 8 cups.
Toss all the vegetables into a large 9x13-inch baking pan (like the kind used for lasagna).
Mix the olive oil, balsamic vinaigrette, maple syrup, and garlic powder in a small container, then pour the dressing over the veggies.
Stir well to coat the vegetables in the dressing.
Bake at 400° F (200° C) for a total of 45 minutes, taking the dish out of the oven and stirring the veggies every 15 minutes.
Serve over rice, mixed with pasta, or as a side dish.
Notes
You can use 8 cups of any type of veggies that you have. It doesn't have to be the specific ones listed in the ingredient section.
If you want to use spinach or other leafy greens, put them in about 5 minutes before the end of roasting.
Save the extra liquid at the bottom of the baking dish to drizzle over the rice.
You may need to slightly adjust the cooking time depending on the size of the sliced vegetables and their water content.
Zucchini, summer squash, and mushrooms have a higher water content, making them juicier; root vegetables and broccoli dry out faster. (A mix of both works well.)