Combine flours, oats, brown sugar, baking soda, baking powder, salt, and cinnamon in a large bowl and stir together until evenly mixed. Add melted butter, plum puree, and eggs, and stir until combined.
Spoon batter into muffin pans (I like to line mine with paper muffin cups and spray the muffin cups with cooking spray). Bake at 375 degrees until a toothpick inserted in the center comes out clean, about 20-30 minutes.
Recipe by Cooking With MicheleĀ® at https://cookingwithmichele.com/2012/09/plum-puree-or-applesauce-muffins/