I have tried all sorts of different ratios of peanut butter in SMBC but no matter what, it renders it so soft!!  The latest I did was 8 oz egg whites, 12 oz sugar, 10 oz butter, 6 oz peanut butter - and STILL too soft.

Anyone make one that works?

AMake your smbc as normal, and then [B]fold[/B] peanut butter in when you're done. You don't make it part of the cooking process, it's just something you add at the end.

ANo measuring necessary, just toss some in when you're done. If you need to make a big batch, then use your mixer with the regular mixing attachment, not the whisk, just to get it evenly mixed in.

Ok, that's pretty much what I did....whipped in the butter, and then added the peanut butter (with the whip attachment).  So maybe try with the paddle instead of the whip?

Thank you -

You just don't want air bubbles getting in, which the whip will do, so I switch to paddle once it's time to add the butter. Maybe you're adding too much peanut butter?

And it's probably going to make it soft no matter what, so unless it's a dessert style cake (simply iced with no decorations), the only thing I ice with on the outside of the cake is normal SMBC. Any flavorings or chunky/fruit type additions are restricted to filling only.

When I tried SMBC with peanut butter, it never had enough flavor for me.  I ended up making a frosting with peanut butter, butter, powdered sugar, vanilla and salt for the filling, and then regular SMBC on the outside.  I figured if I kept adding more peanut butter to get the flavor, it wouldn't work the same.  

When I make peanut butter smbc, I make the smbc, then at the end , I add all natural peanut butter to taste. It is delicious. Anything that you add, it is always at the end. hth