Preheat oven to 350 degrees F. Grease a mini muffin pan.
Cream together sugar and butter. Beat in egg yolks and vanilla.
Add flour, baking soda, and cream of tartar. Stir. Taking a heaping tablespoon and scoop into mini muffin pans. Press a indent with the back of a teaspoon or your thumb.
For apple Pie Filling:
In 10-inch skillet, melt butter over medium-high heat. Add apples and apple pie spice; cook 5 minutes or until apples are tender. Sprinkle with sugar; cook 2 minutes or until mixture is syrupy. Allow to cool completely. Spoon into indented cookies.