In a small bowl, combine the oil, salt, basil, thyme, rosemary, Italian seasoning, black pepper, and garlic powder to create a paste.
Rub the roast all over with the herb paste. Place the roast on a piece of parchment paper (or on a plate) and allow it to chill in the fridge for at least 1 hour.
Preheat the oven to 475 degrees F. Remove the pork loin from the fridge and place it in the center of a large baking sheet.
Roast for 20 minutes. While the pork cooks, add the potatoes, carrots, and onions to a large mixing bowl. Drizzle with olive oil and season with salt and pepper. Toss until well coated.
After the initial cooking time, remove the baking sheet from the oven. Carefully surround the roast with the veggies.
Lower the oven heat to 425 degrees F. Cook for another 30 minutes or until internal temperature reaches 145 degrees F. (see note).
Remove from the oven and transfer the pork loin to a cutting board to rest for 10 minutes before slicing. Transfer the vegetables to a serving bowl and the pork to a platter, or serve on individual dinner plates.
Notes
Nutritional information includes 9 ounces of pork loin and 1/6 of the roasted vegetables per serving.
The second cooking time may vary depending on the size of your roast. If needed, you can remove the vegetables to a bowl to keep warm while the pork finishes roasting.