Pour apple cider into a saucepan and bring to a gentle simmer for 15-20 minutes until reduced to ¼ cup.

Melt unsalted butter in a skillet over low heat until golden brown and nutty, about 5-7 minutes.

Whisk together flour, baking powder, baking soda, cornstarch, apple pie spice, and pinch of salt in a bowl.

In a mixing bowl, whisk brown butter with sugars, then add egg, yolk, reduced cider, and vanilla extract.

Gradually mix dry ingredients into wet ingredients until just combined; the dough will be soft and slightly sticky.

Chill the dough in the refrigerator for 30 minutes; preheat the oven to 375°F (190°C).

Drop dough balls onto a lined baking sheet, spacing 2 inches apart; bake for 9-11 minutes until edges set.

Prepare the glaze by whisking together melted butter and apple cider; mix sugar with cinnamon for coating.

Brush warm cookies with glaze, then dip tops into cinnamon-sugar mixture; cool on a wire rack.