Whenever I have made MFF in the past I had a hard time getting the white choc. to melt evenly. I always had chunks of choc. that didn't melt. I found that I can melt the choc. in the microwave on 1/3 power with the butter and the choc. is creamy. I can then blend it in with the melted cream and gelatin (this is after you let the gelatin bloom and then melt it). (I make my fondant on the stove over a double boiler.) I found that when I pre-melt the choc. I get a smoother base to mix in the pwd. sugar.

You have probably already figured this out but if not I thought I would share.