Preheat the oven to 350℉. Generously spray 8 of the muffin pan cavities with cooking spray, but don't use muffin liners!
In a large bowl, stir together the cocoa powder, oat flour (see note 1), baking soda, baking powder, salt, and brown sugar.
In a separate bowl, combine the peanut butter, applesauce, Greek yogurt, vanilla, honey, and egg. Mix until completely combined.
Add dry ingredients on top of wet and chocolate chips on top of that. Stir until just combined. Transfer the batter into the prepared muffin tin. If desired, top each muffin with a few more chocolate chips.
Bake for 18–22 minutes or until a toothpick inserted in the center comes out clean. Remove and let cool in the muffin tin for 2–4 minutes and then gently coax out onto a cooling rack to finish cooling.
Video
Notes
Note 1: To make your own oat flour, place old-fashioned or quick oats in a food processor or small blender jar. Pulse the oats until they are ground into a powder-like consistency that resembles flour.Note 2: If desired, you can use just applesauce or just Greek yogurt instead of a combination of both, but make sure to still use 1/2 cup measurement of whichever you choose to use.Storage: Store peanut butter muffins in an airtight container at room temperature for 3 days or refrigerate for up to a week.For longer storage, wrap and freeze for up to 3 months. Thaw at room temp or microwave briefly to warm.