Flourless Peanut Butter Chocolate Chip Mini Blender Muffins

"The fastest and easiest batter I've ever made. Combine all ingredients (except the chocolate chips) and blend until smooth. The muffins are gluten-free, grain-free, soy-free, dairy-free, oil-free, refined sugar-free, and they're under 100 calories each (66 calories if you omit chocolate chips). For all the health claims you could make about these muffins, the best part is that they taste every bit as good as muffins made with flour, gluten, and lots of added sugar. The peanut butter flavor is pronounced and bold, while the banana disappears almost entirely. I used mini chocolate chips because they're size-appropriate for the mini muffins...."