If making homemade apple butter, be sure to follow our recipe and leave some time for cooling down! Preheat your convection (fan) oven to 390 degrees F (200 C). Line a baking sheet with parchment paper.
Whip the butter and sugar together in a stand mixer with a paddle attachment or by hand with a whisk.
Add the vanilla extract and mix.
Combine flour, cornstarch, baking powder, and cardamom in a separate bowl and whisk/mix together so there aren't any lumps.
Add dry ingredients to the butter/sugar/vanilla mixture and mix together (very low speed with the paddle attachment, or using a spoon/spatula by hand) until no dry spots remain. The dough should come together easily and be sort of a play-doh consistency. If it's feeling sticky, you may want to add another tablespoon of flour.
If the dough is getting really soft at this point, you can put it in the fridge for about 10-20 minutes before shaping the cookies. We would also recommend this if it is warm in your kitchen or you are making these in the summertime!
Divide the dough into 12 even balls and spread them out evenly on the baking sheet. Now you may have to warm up the dough a little bit in your hands to prevent cracking when you press them down in the next step. It's a delicate temperature balance!
Using your thumb, make an indentation in each ball, flattening out the center of each cookie and making room for the apple butter. If the cookie is cracking a lot, re-roll the ball so it's a little bit warmed up in your hands and try again. You can also press together any bigger cracks with your fingers!
If you notice that your dough is softening/looking shiny, now is also a good time to pop the cookies in the fridge for 10-15 minutes.
Spoon the apple butter into the indentations. We aim to fit about 1/2-1 teaspoon of filling in each cookie.
Bake for 10-12 minutes or until very lightly golden on the edges. Allow the cookies to cool on the baking sheet for 5-10 minutes before moving to a cooling rack to help them set.
Optional but highly recommended: after the cookies have cooled, make a simple cinnamon icing by adding about 1 cup of powdered sugar, a few dashes of cinnamon, and a splash of water to a bowl. Mix together until you have a thick but drizzle-able consistency.
Drizzle over the cookies and enjoy!