Set the water to heat, dissolve the nut butter in it. Meanwhile, rinse the millet well and drain. Place the millet in a pressure cooker and heat it on high heat to toast it. Stir constantly until it pops a little or you see it starting to brown up a bit. Add the water, kombu and salt, and lock the lid in place. On high heat, bring to high pressure (second red bar) and turn to low to maintain pressure for 9 minutes. Turn off the heat and allow the pressure to come down naturally for about 10 minutes. Remove the lid, and fluff. Compost or thin slice the kombu for salad.