Preheat oven to 325° F. Prepare baking sheets by spraying with non-stick cooking spray or covering with parchment paper. Set aside.
In a stand mixer, cream together the butter and brown sugar. Add egg yolk and vanilla and mix until just combined. Add beer and mix again until just combined.
Add both flours, baking soda, baking powder, salt, cinnamon, and cornstarch and mix until just combined.
Scoop out cookie dough by the rounded tablespoon full onto prepared cookie sheets.
Bake at 325° F for 12-14 minutes. Immediately remove cookies from cookie sheet after baking and allow to cool to room temperature.