Preheat oven to 425ºF and pour 1-2 tablespoons of oil evenly across a sheet pan. Cube sweet potatoes (1” size or smaller) and cut brussel sprouts in half. Place tenderloin in the center and arrange potatoes and sprouts around it. Drizzle with oil, toss to coat, then season with salt and pepper to taste. Place sprigs of rosemary and thyme all around as well as thin slices of sage leaves and minced garlic.
Bake in preheated oven for 20-25 minutes. After first 10 minutes, flip over tenderloin, sweet potatoes and Brussel sprouts for even cooking. Allow pork to rest for 5 minutes before slicing into 1-inch sections and serving.