Preheat the oven to 425°F and prepare two baking sheets by lining them with parchment paper for easy cleanup.
Arrange the beets and carrots on one baking sheet, while placing the parsnips, sweet potato, and turnip on the other. Drizzle each group of vegetables with olive oil, ensuring an even coating. Sprinkle the rosemary, sage, and thyme over the vegetables, followed by generous pinches of sea salt and a few twists of freshly ground black pepper. Toss everything together so the flavors meld, then spread the vegetables out in a single layer for optimal roasting.
Place both trays in the oven and roast until the vegetables are tender and slightly caramelized around the edges. The parsnips, sweet potato, and turnip will cook faster, so start checking for doneness around 25 minutes. The beets and carrots will take longer, requiring closer to 50 minutes.
For the crispy sage, line a plate with paper towels. Heat the olive oil in a small saucepan over medium heat until it starts to bubble. Carefully drop in the sage leaves, stirring gently, and cook for about a minute until crisp. Using a slotted spoon, transfer the fried sage leaves to the prepared plate to drain, reserving the infused oil.
Once the vegetables are done roasting, remove them from the oven and drizzle with a tablespoon of the reserved sage oil, tossing to distribute the flavor. Arrange the roasted vegetables on a serving platter and garnish with the crispy sage leaves. Serve warm for a comforting and flavorful dish.