1. Preheat your oven to 200°C (400°F).

2. In a small bowl, mix together the granulated sugar, kosher salt, and ground white pepper.

3. Line a baking sheet with aluminum foil or parchment paper. Place the salmon fillet on the prepared baking sheet and sprinkle the sugar mixture evenly over the top, ensuring the entire surface is covered.

4. Spread half of the chopped dill over the salmon, covering it evenly. Set aside the remaining dill for garnish.

5. Bake the salmon in the preheated oven for 12-15 minutes, or until the flesh flakes easily with a fork and reaches your desired doneness.

6. While the salmon is baking, wash and chop the potatoes into bite-sized pieces. Place them in a large pot and cover with water. Bring to a boil over high heat, then reduce the heat to medium-low and let simmer for 15-20 minutes, or until tender when pierced with a fork.

7. Drain the potatoes and return them to the pot. Add the unsalted butter and gently toss until the potatoes are evenly coated. Season with salt and pepper to taste.

8. Remove the salmon from the oven and garnish with the remaining dill. Serve immediately with the buttered potatoes and lemon wedges on the side.