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.
While water boils, it's the same process, but (!!) particles jump of into air in the entire liquids volume. Which means that even on bottom of your liquid, you can find particles that have so high energy that they jump into gas state (that's why you see bubbles while water is boiling).