Preheat your oven to 350°F (175°C). Line a muffin tin with paper liners or lightly grease it.
In a large bowl, mix the oat flour and baking powder.
Add the applesauce and honey (if using) to the dry ingredients. Stir until combined.
Gently fold the frozen berries into the batter. Be careful not to overmix to prevent the berries from breaking up too much.
Divide the batter evenly among the muffin cups.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool in the pan for a few minutes, then transfer them to a wire rack to cool completely.
Serve and enjoy!