Preheat your oven to 400 degrees Fahrenheit. Line a large rimmed baking sheet with parchment paper or a silicone mat to ensure the vegetables do not stick and to make cleanup easier after your Christmas feast.
Wash all your produce thoroughly. Cut the potatoes and Brussels sprouts in half, and slice the carrots and parsnips into uniform rounds about half an inch thick. Making sure the pieces are similar in size ensures that everything cooks evenly in the oven.
In a large mixing bowl, combine the potatoes, carrots, parsnips, and Brussels sprouts. Drizzle the olive oil over the top and add the minced garlic, rosemary, thyme, salt, pepper, and smoked paprika. Use your hands or a large spoon to toss everything together until every piece is well coated in the herb oil.
Spread the seasoned vegetables out onto your prepared baking sheet in a single layer. It is important not to crowd the pan, as the vegetables need space for the hot air to circulate so they roast rather than steam.
Place the tray in the oven and roast for 30 to 35 minutes. Halfway through the cooking time, use a spatula to toss the vegetables gently so they brown on all sides. They are done when they are fork-tender and have beautiful charred edges.
Remove the tray from the oven and let it sit for a minute. Transfer the vegetables to a festive serving bowl and sprinkle with a little extra fresh thyme if desired before bringing them to the Christmas table.
