I don't have a great deal of time to look for the recipe right now but there are muffin recipes on the recipe board (finger food) which have no sugar added, you can sub the oil/butter part for peanut butter or just mix some through. The basic sugar free muffin recipes are easily adapted to switch the fruits/veg etc that are in them.
You could also mix some peanut butter though some oaty chews (recipe on teh thread, again easily adapted, add anything really!).
WRT safety, I would agree that caution needs to be taken with the texture of peanut butter, first it should be smooth not crunchy and second it needs to be either incorporated or spread very thinly so that a big glob doesn't get caught in LOs mouth causing a possible choke hazard.
Peanut butter is nice added to curry for a satay feel...it need not be spicy, maybe look up some satay sauce recipes and see if you can adapt one for LO? Or just peanut butter mixed with coconut cream to thin down into a sauce.
I wasn't sure if you meant the peanut butters or the muffin recipes contained sugar. You can certainly find both sugar free. Sunpat for instance is sugar free, there are other brands too. also watch for additional oils, salt etc. not all nut butters are equal