I like to put some plain batter in the bottom of the cups first, then add blueberry batter mix. That prevents having blueberries cook unto the bottom of the cups. I have substituted about 1/3 cup to 1/2 cup applesauce for some of the oil.
Can make using rhubarb then add 1 tsp. cinnamon to the dry ingredients.
Mix oil and eggs until well blended then fold in oatmeal and juice mixture and mix well. Add dry ingredients and mix until just combined. Fold in blueberries last. Top with a mixture of cinnamon sugar and nuts if desired.
Bake 375 degrees for 20-25 minutes or until test done.