I got this recipe from my ex's mother. She made great Christmas cookies.
Cornstarch does the heaviest structural work in this dough. High starch content inhibits gluten development when combined with flour, preventing chewiness and yielding a distinct crumbly texture. Without this ratio, the cookies lose their signature tender bite.
Achieving the correct consistency requires proper fat creaming. Beat the margarine and the initial 1/3 cup of powdered sugar until pale and aerated before adding dry components. Drop small portions onto an ungreased baking sheet and press each center with a thumb or thimble to create a well.
Bake these pastries at 350 degrees Fahrenheit for 12 to 15 minutes. Watch for the edges to set firmly while maintaining a pale color, avoiding any deep golden browning. Cool them completely on a wire rack before filling the indented centers with the remaining cream cheese and powdered sugar frosting.
Margarine can be substituted with an equal weight of unsalted butter at a one-to-one ratio if dairy fat is preferred over vegetable oil spreads. Store finished baked goods in an airtight container at room temperature for up to four days.