01 -
Heat the oven to 375°F. Grease a 24-cup mini muffin pan well, or use silicone liners.
02 -
Add the oats, baking powder, baking soda, and cinnamon to a high-speed blender. Blend until the oats look like a coarse flour.
03 -
Add the bananas, applesauce, eggs, yogurt, oil, vanilla, and spinach. Blend until smooth and bright green, stopping once or twice to scrape down the sides.
04 -
Let the batter rest for 3 minutes. If it is very thick, blend in 1 tablespoon milk at a time until it looks like thick pancake batter.
05 -
Scoop the batter into the prepared pan, filling each cup about two-thirds full. Do not overfill, or the centers may stay gummy.
06 -
Bake mini muffins for 10-12 minutes, until the tops spring back and a tester comes out mostly clean. Standard muffins take about 16-18 minutes.
07 -
Cool in the pan for 10 minutes, then move to a rack. Serve warm or fully cooled, cut into age-appropriate pieces for babies.