In a mixing bowl, combine the butter, shortening, cream cheese and sugar, blending well until light and fluffy. Add egg and vanilla and blend. In a bowl, combine the flour, cream of tarter, baking soda and salt. Mix to combine, and then slowly add it, a little at a time to the wet mixture. Mix until well blended. Scoop into a bowl, cover and refrigerate for several hours or overnight. For the filling, mix together the remainder of the cream cheese (6 oz), powdered sugar and vanilla. In another bowl, combine 1 tablespoon of cinnamon and 3 tablespoons of sugar. To assemble, pour some cinnamon sugar into a baking sheet or plate. With the remainder of the cinnamon and sugar, add sparkly decorative sugar if available. (The sparkly sanding sugar is optional) then place in a shallow dish. Scoop a well-rounded tablespoon of dough and roll into a ball. Plate the dough ball on the baking sheet with the cinnamon sugar combination. Flatten the dough to a 2-inch in diameter disc. Spoon a small amount (about a half a teaspoon) of filling onto the disc, seal it and roll it back into a ball. Roll it into the cinnamon sugar mixture (with the sparkly sugar). Place the dough balls on a parchment or silpat lined baking sheet about 2 inches apart. Bake at 350 degrees for about 12-14 minutes or until edges just begin to turn brown. Remove the cookies from the oven and place on a cooling rack. When cooled, store the cookies in an airtight container. Yields approximately 16 cookies.