Preheat oven to 375 degrees F. Lightly oil a standard 12-cup muffin pan, or use paper liners or a silicone muffin pan.
Place dried cherries in a small bowl and cover with warm water. Set aside.
Place ½ cup pistachios in the bowl of a food processor. Process until the consistency of coarse crumbs. This won't take long; stop periodically to make sure it's not turning into pistachio butter! Once the pistachios are ground, add the oat flour, baking powder, baking soda, and salt. Pulse several times to incorporate. Set aside.
In a large mixing bowl combine the applesauce, milk, vinegar, vanilla, and maple syrup. Set aside.
Drain the cherries well. Roughly chop the cherries and the remaining ½ cup pistachios, reserving a handful of nuts for decorating the tops of the muffins.
Whisk the wet ingredients again to reincorporate the heavy maple syrup, then add the dry ingredients to the mixing bowl. Whisk until there's no dry flour. Fold in all of the cherries and the larger amount of pistachios. Scoop about ⅓ cup batter into each muffin cup, filling them almost ¾ full (you might have a bit of batter leftover; see Notes on how to make a bonus microwave muffin with it). Sprinkle reserved pistachios on top of each muffin.
Bake for 17 to 19 minutes or until the tops are firm when lightly pressed. Allow to cool in the pan for 5 minutes, then transfer to cooling racks.
You should have just enough batter leftover to make a small 13th muffin. Let's call it our baker's treat! You can either pour the batter into an oven-safe ramekin or mug and bake it with the other muffins, or microwave for about 1 minute (keep a close eye on it). If you choose the microwave method, allow to cool for 1 to 2 minutes, then dig in. :D
Store pistachio muffins in an airtight container at room temperature for up to 3 days or refrigerated for up to 5 days. Muffins can also be frozen.