Ingredients: (Makes 12 muffins) 1 cup whole wheat flour 1 cup all purpose flour 1 teaspoon baking powder ½ teaspoon baking soda dash of cinnamon  ⅛th teaspoon salt 2 medium overripe bananas mashed  2 medium apples grated (with skin) (approximately 1.5 cups grated) ½ cup oil (used canola) ½ cup packed brown sugar (or to taste) ¼ cup of chopped walnuts (optional and can use any nuts of choice like pecans, almonds) ¼ cup of milk  For Streusel topping :  1 tablespoon butter 1 tablespoon all purpose flour 2 tablespoon brown sugar Method:  Preheat the oven to 350F. Line a muffin/cupcake tray with liners and keep it ready.  In a separate bowl, add the dry ingredients like whole wheat flour, all purpose flour, baking powder, baking soda, salt and cinnamon. Mix everything well together and keep aside.  In a mixing bowl add the mashed banana (use a fork to mash) followed brown sugar and oil. Mix well using a whisk. 
Then add the grated apples followed by milk and mix well.  Now add the dry mixture to the wet mixture. Combine everything using a spatula. (do not over mix). Add chopped walnuts and gently fold the mixture so that walnuts are nicely incorporated. 
For making the streusel mixture, mix all ingredients mentioned under “Streusel topping” and using your hand or fork mix till you get a crumbly mixture. Keep aside. Scoop the batter into the pre-lined muffin tray. Fill each muffin liner till ¾th full.  Top each muffin with equal amount of streusel and with some walnuts. Bake at 350 for 30-45 mins or until done i.e. toothpick inserted in the center of muffin comes out clean without any batter stuck on it. Let them cool in the tray for 10 mins and then transfer on to a cooling rack. Serve or store in airtight container for upto 3-4 days. Or freeze upto 2 weeks for later use. 
Notes: 

Don’t over mix the batter as that may result in hard muffins. The more ripe the bananas are the better and sweeter they are. Mine had almost black skin on them. The sweetness of banana and apples can vary so taste the mixture before adding sugar and adjust to your taste. For me ½ cup sugar worked perfect.  Addition of nuts gives the nuts a nice crunch. Any nuts of choice can be used You can even chop the apples instead of grating. With or without skin is as per your preference.  You can even make these muffins without the streusel topping.  I’ve used less streusel but you can double it for more quantity.  My family is not so fond of cinnamon hence i have added very little  but you can amp it up to your taste. 

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