Method
1) Beat butter, brown sugar, bananas, vanilla essence and eggs together in a mxing bowl till bananas are crushed and well mixed.
2) In another bowl, mix flour, strawberries, baking powder, sodium bicarbonate and cinnamon powder together.
3) Add the dry ingredients (flour etc) into the beaten butter batter and mix well. Do not overmix as this will toughen the protein in flour making muffin tough and hard.
4) Scoop muffin batter into prepared baking cups till 2/3 full.
5) Bake in oven at 180C (356F) for 30 to 35 minutes for a large sized baking cup or 20 to 25 minutes to a regular sized paper cup.
6) Insert a skewer into the middle of muffin to check for doneness. If skewer comes out clean it is done.