And I really like the taste & texture. And it really wasn't as hard as I thought it would be. Now, of course I did this without planning, b/c I'm still baking, so I won't be ready to use the IMBC until tomorrow. It's in the fridge. Will it harden up since it's mainly butter? Do I have to let it come to room temp before trying to use it? Will i have to rebeat it?

Ok so Im about to ask a silly question but what is IMBC? TIA MC

IMBC is italian meringue buttercream.

I made a batch two days ago and it's still fine so yes it will keep nicely. Some people keep theirs in the fridge but I didn't have to. No it won't harden up at all.

Sorry Italian Meringue Buttercream. Basically it's made by pouring hot sugar syrup into beaten egg whites and adding butter. It's not as sweet as a crisco based icing.

just let it come back to room temp. gently whip if necessary.

It will harden up in the fridge. Just set it on the counter until it is room temp and then rewhip gently to avoid too many air bubbles

thanks for your help!

I read in another post that if you try to whip it before it has come all the way to room temp, it will break down. So give yourself enough time. Good luck. Keli

This is going to be a stupid question, however here goes. The sugar called for in Sylvia Weinstock's Buttercream recipe, it is powdered or granulated?

granulated

Update - kelliames was right. I took it out of the fridge, let it set 3 1/2 hrs on the counter b/c i had to go to a wake. Tried to rewhip and it totally broke down! My beautiful IMBC became a watery, clumpy mess!! I had to make the crisco version b/c I didn't have any more butter and nothing is open at 9:00 at night! I thought for certain it was at room temp - guess it's a little cold in my house?