Double Chocolate Black Bean Muffins

My family likes these chocolatey muffins; I wish I'd known about this recipe last fall when I needed to make something vegan and allergy-friendly for my son's class. The muffins I've made so far haven't been vegan; I used butter instead of coconut oil. A few observations:

1. A 14.5-oz can of black beans has a little bit more than enough for two batches of muffins, so you may as well make a double batch.

2. The recipe is written as a one-bowl (food processor or blender) recipe, but I would rather add a bowl to the procedure. It's easier for me to clean a food processor or blender that had runny liquids in it rather than a thick batter, plus it's easier to use my 1/4-cup muffin scoop out of a wide mixing bowl rather than a narrow appliance bowl or pitcher.

3. For one batch, I mixed in all of the chocolate chips into the batter rather than reserving a few for sprinkling on top. For the other batch, I sprinkled the chips on top and they really did make a nice difference in the muffins' appearance; they look more dessert-like.