The closest spread to peanut butter I've found in terms of flavor and texture is sunflower seed butter. It's also relatively easy to find; I've seen it in large chain grocery stores right next to the peanut butter.
A curmudgeon with years of practice. The bubbles in boiling water are steam or vaporized water. The bubbles initially do not reach the surface of the billing fluid as the colder water away from the hot bottom cools the steam turning it back to liquid. WHen all the water is at 100oC the bubbles reach the top.
Once the initial run of bubbles made by the dissolved gases from air or from subterranean sources have been exhausted and the temperature of the water gets higher or approaches the boiling point at 100 degrees C, the pressure in the water nears the atmospheric pressure.