2 tsp. freshly chopped rosemary, plus more for garnish
1/4 tsp. red pepper flakes
Preheat oven to 400°. Season tenderloin on both sides with salt and pepper. Place potatoes in a 9”-x-13” baking dish and drizzle with 2 tablespoons oil and season with salt and pepper. Place tenderloin on top.
In a small bowl, whisk together remaining ½ cup oil, maple syrup, garlic, mustard, rosemary, and red pepper flakes. Season with salt and pepper then brush over tenderloin.
Roast for 1 hour or until potatoes are tender and tenderloin is cooked through. Internal temperature should read 145°.