Preheat your oven to 400°F and line a baking sheet with parchment paper.
Peel the carrots and parsnips, then slice them into 1-inch thick rounds.
In a mixing bowl, toss the sliced root vegetables with the sea salt, black pepper, minced garlic, and half of the fresh thyme and rosemary.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 20 to 25 minutes until they are tender and caramelized.
While the vegetables are roasting, place the duck leg confit skin-side down in a cold cast-iron skillet.
Turn the heat to medium-low to slowly render the fat and crisp the skin, which should take about 8 to 10 minutes.
Once the skin is deep golden and crispy, flip the duck leg and cook for an additional 2 to 3 minutes until the meat is heated through.
Plate the roasted carrots and parsnips and place the crispy duck leg on top.
Finish the dish with a light drizzle of balsamic vinegar and a garnish of the remaining fresh herbs.