Pour the apple cider into a small saucepan and heat it over medium-high heat until it reaches a gentle boil or simmer. Continue cooking until it reduces down to ¼ cup, which takes about 15-20 minutes, then remove from heat and let cool.

In another saucepan, melt the butter over low heat until it begins to foam; whisk frequently as it becomes fragrant and develops nutty notes with lightly toasted bits at the bottom before transferring it to a heat-safe bowl to cool.

In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, cornstarch, spices, and salt until well blended; this ensures even distribution throughout your cookie dough.

In a large mixing bowl, combine cooled browned butter with light brown sugar and granulated sugar using a whisk until fully blended; then add egg, egg yolk, reduced apple cider, and vanilla extract mixing until smooth.