Preheat oven to 400°F. Cut off top of butternut squash and cut in half lengthwise. Remove seeds and membranes, set on your baking sheet, drizzle inside with olive oil and sprinkle with salt. Bake for 10 to 15 minutes until slightly softened. Let cool. Peel butternut squash and cut into 1/2-inch cubes.
Meanwhile, cook pasta according 1 minute short of package instructions. Drain and set aside.
Preheat saucepan over medium heat, add butter and let melt, add garlic and sauté for 1 minute. Add flour and mix until well blended; add cream and broth, continue cooking and stirring until smooth and thickened.
Add 2 cups Grand Cru and 2/3 of dill and stir until well combined. Season to taste.
In casserole dish, add butternut squash, pasta, smoked salmon, cheese sauce and mix well, sprinkle remaining 1 cup Grand Cru over the top and bake for 30 minutes.
Remove from oven and sprinkle with remaining dill before serving.