Brown the butter in a saucepan over medium heat, 5-7 minutes, until amber and nutty-smelling.
Pour into a bowl and cool 15-20 minutes until no longer warm.
Whisk flour, baking powder, cinnamon, and salt in a separate bowl.
Whisk both sugars into the cooled butter, then add eggs and vanilla until smooth.
Stir in dry ingredients just until combined. Chill at least 2 hours, up to overnight.
Scoop into 1 1/2-tbsp balls, roll in powdered sugar, place 2 inches apart on a parchment-lined sheet.
Bake 10-12 minutes until edges are set and tops have cracked.
Cool on the sheet 5 minutes, then move to a wire rack.
