- Preheat the oven to 425 degrees. Cut the potatoes into 1-inch cubes. Chop the rosemary and garlic. Halve, peel, and cut the onion into wedges.
- Season the pork with salt and pepper. Place the pork in a bowl with 1 teaspoon olive oil, half the garlic and rosemary.
- Place the potatoes in a pot with cold water. Season with a pinch of salt and bring to a boil. Cook for 10 minutes. Once the 10 minutes are up, drain.
- Remove the pork from the bowl, removing any large pieces of garlic and rosemary. We’re going to sear the pork so removing them will prevent from burning. Heat 1 tablespoon oil in a pan over medium-high heat. Sear the pork for 2 minutes per side until golden brown.
- While the pork sears, toss the potatoes and onions with 1 tablespoon olive oil, remaining garlic and rosemary on a baking sheet. Season with salt and pepper. Roast for 10 minutes, until crispy. When the pork is seared on all sides, place it on the baking sheet and continue to roast, about 6 more minutes.
Finish: In a bowl combine 1 tablespoon olive oil with mustard and balsamic vinegar. Whisk to combine and season with salt and pepper. Toss the arugula in the dressing. Thinly slice the pork and serve along with potatoes and onions and arugula salad.