I may be chasing an unnecessary dream here, but I thought I'd give this a try. I found a nice-sounding Passover Devil's Food cake recipe with a peanut butter frosting. I was thinking of making almond butter from scratch this year, so I thought I'd take a peanut butter frosting recipe and just sub in the almond butter. The problem is that just about every recipe uses confectioners' sugar. I've made KP confectioners' sugar in the past by whizzing up some regular sugar and potato starch in the processor. I'm concerned, though, that in the quantities called for in a 2-layer cake frosting recipe, the mock confectioners' sugar may not work as well.
Has anyone tried to use the DIY sugar in a frosting recipe and how well did it work? Or, barring that, do you have a nut butter frosting recipe that is Pesachdik? If necessary, I'll just make a 7 minute frosting, but why do anything the easy way?