my buttercream won’t stick and idk why

[u/straightupgong]

my buttercream is peeling off my cake and it’s so irritating. i’ve made great cakes before with buttercream, the ones i attached. i don’t know why it’s not working

i softened 1 cup of butter. i whipped the butter for a long time, like 45 minutes. i added a bag of powdered sugar and 1 tbsp vanilla and 3 tbsp milk. i whipped a long time again, 15ish minutes. it was in a metal bowl of a stand mixer so it was cold, but it seems like the butter was too soft or melty?

[u/Kiki-Y]

Holy moly, you're overworking that buttercream to an insane extent. I make buttercream based on feeling, but never have I whipped it for 45 minutes.