Pour the apple cider into a small sauce pan. Heat the apple cider to a gentle boil or simmer over medium-high heat. Continue to cook the cider until it reduces down to ¼ cup (59 ml). This takes about 15 - 20 minutes. Remove from the heat, pour into a small bowl or measuring cup and set aside to cool to room temperature.
In a sauce pan or pot, melt the butter on low heat until the butter begins to foam. Once it starts to foam, whisk or stir the liquid butter frequently. The butter will begin to smell nutty and very fragrant. Once the foam has subsided, the butter should have some brown, lightly toasted bits floating at the bottom.
In another bowl whisk together the flour, baking powder, baking soda, cornstarch, ground spices and salt until well combined.
In a large mixing bowl, whisk in the cooled browned butter with the light brown and granulated sugars until well combined.
Stir the dry ingredients into the wet until just combined.
Using a medium cookie scoop (2 tablespoons, 30 ml), scoop the cider cookie dough and place onto lined baking sheet about 3 inches apart.