01 -
Add the butter, granulated sugar, and light brown sugar to the bowl of a stand mixer fitted with a paddle attachment. Beat on medium-high speed for 2-3 minutes. Add the vanilla extract and eggs, then beat for another 1-2 minutes until light and fluffy.
02 -
Whisk the cake flour, cornstarch, baking soda, baking powder, and kosher salt in a medium bowl until combined. Gradually add the dry ingredients to the wet ingredients and beat on medium speed for 1-2 minutes, scraping down the sides as needed. Cover and chill the dough for 1 hour.
03 -
Preheat the oven to 350°F (175°C) and line two large baking sheets with parchment paper.
04 -
Add the filling ingredients (softened butter, light brown sugar, cinnamon, and cake flour) to a medium bowl and stir until smooth. Scoop and roll the filling into balls (about 2 teaspoons each) and set them on the prepared baking sheet.
05 -
Scoop the chilled dough using a 1/4 cup measuring spoon or a large cookie scoop. Divide each scoop in half and create a well in one half. Place a filling ball in the well, cover with the other half of the dough, and pinch the edges to seal. Roll into a ball.
06 -
Place the dough balls on the baking sheets about 2 inches apart. Bake for 11-13 minutes, until the edges are golden and the tops are just set. Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
07 -
Whisk together the powdered sugar, cinnamon, melted butter, and milk until smooth. Spoon the glaze over the cooled cookies and let it spread to the edges. Allow the glaze to set for 15 minutes before serving.