Makes: 12 servings. Prep: 15 minutes. Cook: 15 to 20 minutes. Bake: at 350° for 45 minutes. Stand: 15 minutes.
Heat oven to 350°F. Coat 13 x 9 x 2- inch glass baking dish with nonstick cooking spray.
Place potatoes in a large pot with enough water to cover. Lightly salt and bring to a boil. Lower to simmering; cook for 15 to 20 minutes or until fork tender. Drain.
In large bowl, mash potatoes with hand mixer. Add butter, half-and-half, cream cheese, garlic salt and nutmeg. With mixer, beat potatoes on medium-high speed until very smooth. Spoon into prepared baking dish.
Bake at 350°F, uncovered, for 30 minutes. Sprinkle sliced almonds over casserole; bake an additional 15 minutes, uncovered, until lightly browned.
Let stand 15 minutes before serving. Garnish with chopped chives if desired.