In a large skillet over medium heat, melt butter. Add sausage and brown, stirring occasionally. Pour in half & half and bring to a simmer. Add cream cheese, allow to melt, and stir occasionally.
Sprinkle in garlic powder and stir. Let sauce cook and thicken for about 5 minutes. Stir in parmesan cheese until combined. Season with salt and pepper to taste. Add cooked pasta, mix well, and serve immediately.