114 g butter-flavored shortening (soft real butter is fine too, or use half of each)
50.0 g granulated sugar, plus more for dusting
100 g granulated sugar
1 egg
5.0 ml vanilla
5.0 ml cream of tartar (plus a little shake for the egg)
1.12 g baking soda
cinnamon for dusting
3.0 g salt (Morton kosher)
Instructions
Separate the egg and put the white in a mixing bowl along with a little shake of cream of tartar (NOT the full teaspoon yet). Beat the white to soft peaks. Put in the 50.0 g sugar and beat again — the foam may deflate a bit, but if you keep whipping you should get soft peaks again. Set this meringue aside.
In a different mixing bowl, whip the shortening with the 100 g sugar until very fluffy. Beat in the egg yolk, vanilla, teaspoon of cream of tartar, baking soda, salt and flour. Roll the dough into 5-6 big balls.
Prepare the coating by mixing about one part cinnamon to two parts sugar. Roll each ball around in the coating, and then set them on a parchment-lined baking sheet. Slightly flatten each ball into a thick puck.
Bake at 400ºF/200ºC (convection, ideally) for 3-4 minutes, then back the heat down to 350ºF/180ºC until the cookies are done. (They bake almost as well if you do 375ºF/190ºC the whole time.)
Be careful not to overbake these or they will be hard when cooled. Wait until they start to spread and crack, and watch the raw dough exposed by the crack — when it just barely doesn't look wet anymore, that's a good sign they're done. Mine took 12 minutes. Let them cool!