Step 1

In a large bowl, beat together the shortening, butter, sugars, salt, baking powder, and vanilla.

Step 2

, When thoroughly blended, add the egg, beating until fluffy.

Step 3

, In a medium bowl, whisk together the flour and cornstarch. Add to the butter mixture, stirring until thoroughly combined.

Step 4

, Divide the dough in half. Shape each half into a disk, wrap well, and refrigerate for 30 minutes.

Step 5

, Preheat the oven to 350°F. Lightly grease two baking sheets, or line them with parchment.

Step 6

, Place the chilled dough on a lightly floured surface and roll it 1/8” thick.

Step 7

, Cut with cookie or biscuit cutters, spacing the cookies quite close together on the prepared baking sheets; they won’t spread much.

Step 8

, Bake the cookies for about 10 minutes, until they’re very lightly browned on the edges.

Step 9

, Remove the cookies from the oven and cool them on racks.

Step 10

, Store cookies in an airtight container at room temperature for up to one week; freeze for longer storage. The dough may also be frozen: wrap the disks airtight and freeze for up to three months; thaw to room temperature before using.