I made a cake and buttercream frosting 6 days ago for my niece's 1st birthday party. Unfortunately the party was rescheduled because the little one wasn't feeling well.
I froze the cake and defrosted it, and it looks fine, but Im worried about the frosting.
The icing is made from butter and powdered sugar- Ive had it out of the fridge for 3.5 hours and it less cold but still firm. How many more hours will it probably need outside the fridge to get smoother and warmer? Should I add some milk?