Your noisette butter is now ready for use, or it can be kept easily in the fridge for several days.
Remarks
You can avoid cooling the pan in stage 7 by filtering the noisette butter immediately into another (cold) container.
You can also use slightly salted butter, but do be aware that the cooking to noisette stage will concentrate the initial saltiness.
You will have noticed how hot the butter gets towards the end of cooking — a bit like making caramel — so I advise you not to make it when there are young children in the kitchen.