Preheat oven to 400 degrees F. In a large bowl cut cream cheese and ¾ cup of butter into 2 ¼ cups of flour using a pastry blender or 2 forks. The mixture should resemble coarse crumbs.

Flatten dough into a flat circle. Wrap in plastic wrap and refrigerate for 1-2 hours.

Roll dough out to be around 13x9 inches and ½ inch thick. Press into a greased 13x9 inch pan. Prick holes in dough using a fork.

Bake crust alone for 10 minutes.

While crust is baking, melt the rest of the butter. Mash potatoes, butter, and all remaining ingredients except marshmallows. Mix until combined. Pour over crust.

Bake 30 minutes or until lightly brown. Top with marshmallows and broil for 2-3 minutes , or until browned.