Preheat the oven to 450°F. Wash and dry the fresh produce. Line 1 sheet pan (or 2 sheet pans for 4 servings) with foil. Place a large piece of foil on a work surface. Place the blueberries, balsamic vinegar, sugar, and butter on one side of the foil. Add 1 teaspoon of water (or 2 teaspoons for 4 servings). Season with salt and pepper; toss to combine. Fold the foil in half over the blueberry mixture. Fold the three open edges inwards to completely seal the packet. Transfer the foil packet to one side of the sheet pan.

Pat the pork dry with paper towels. Place on the sheet pan(s) next to the foil packet. Drizzle with olive oil and season with salt, pepper, and half the quatre épices; turn to coat. Transfer the sweet potatoes to the other side of the sheet pan(s); arrange in an even layer. Drizzle with olive oil and season with salt, pepper, and the remaining quatre épices. Toss to coat. Roast 18 to 24 minutes for medium (the center may still be slightly pink), or until the pork is cooked to your desired degree of doneness, the blueberries are softened, and the potatoes are tender when pierced with a fork. Remove from the oven. Carefully open the foil packet; stir to combine. Taste, then season with salt and pepper if desired. Transfer the roasted pork to a cutting board and let rest at least 5 minutes. Find the lines of muscle (or grain) on the rested pork; thinly slice crosswise against the grain.

Just before serving, in a large bowl, whisk together the white balsamic vinegar and 1 tablespoon of olive oil (or 2 tablespoons for 4 servings). Add the arugula; season with salt and pepper and toss to combine. Serve the sliced pork with the roasted sweet potatoes and salad. Top the pork with the blueberry sauce. Garnish the salad with the peppers and goat cheese (crumbling before adding). Enjoy!