Preheat your oven to 425°F and position racks in the upper and lower thirds. Line two large baking sheets with parchment paper to prevent sticking and make cleanup effortless for your post-feast rest.
In a large bowl, combine the garlic powder, dried thyme, paprika, salt, and black pepper. Whisk in the olive oil, balsamic vinegar, and maple syrup to create an even coating that will caramelize beautifully during roasting.
Add all prepared vegetables to the bowl with the seasoning mixture and toss thoroughly until every piece is coated. Make sure the sweet potatoes and beets are evenly distributed so nothing burns on one sheet while staying raw on the other.
Divide the thanksgiving roasted root vegetables crowd between the two prepared baking sheets in a single layer, spacing them at least an inch apart. This arrangement ensures hot air circulates completely around each vegetable piece.
Roast for 35-40 minutes, stirring halfway through and rotating the baking sheets between oven racks. The vegetables are done when golden brown and fork-tender, with caramelized edges that practically melt in your mouth.
Remove from the oven and immediately sprinkle the fresh chopped rosemary over the hot vegetables. Transfer to a serving platter and drizzle any pan juices over the top for extra flavor and moisture.