Preheat the oven at 180 C/350 F.
Sift flour, baking powder and baking soda together.
Add banana, milk and jackfruit to your food processor and prepare fruit puree.
Add oil, banana-jackfruit puree, and vanilla essence in a mixing bowl and mix well.
Add sugar and mix well. Now add sifted flour slowly to the bowl and fold. Do not over mix.
Keep 2 tablespoons of blueberries aside and add the remaining in the mixing bowl. Give a quick stir.
Grease the muffin cups evenly with little oil or use liners and pour the batter in each cup. Make sure you fill only ¾Th of each muffin cup. Add few blueberries on the top.
Now bake in the oven for 25-30 minutes. Remove from the oven and allow the muffins to cool completely. Muffins are ready!