I'd say we have tunafish about 1Xmonth or less. We aren't too keen on PB but DD gets nut butters (cashew, sesame, almond, etc.) often enough.
DD took a while to develop a taste for bread so nut butter sandwiches took a while - prob'ly about 2 years old before she had more than a bite of a PB (Nut butter) & J.
We have mixed 1/4 cup sesame paste (tahini) with a tablespoon or so of miso - YUM (I got this from Cythia Lair's Feeding the Whole Family).
Most of the time DD gets nut butters on a spoon.