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.
This technique cooks food at a relatively high  temperatureâ212 degrees is the boiling point for water at sea level. When liquids boil, bubbles break through and pop on the surface while the whole batch of liquid churns vigorously. Bubbles are caused by water vapor, a gas, rushing to the surface. What boiling does.