Pre-heat the Oven to 170 °C. Line the muffin tray. Since I had individual muffin cups, I greased them and put them in my baking tray. I didn't use liners.
In a saucepan, melt the butter & allow to cool too room temp.
Mix together cornstarch, warm water & oil in a small bowl. Keep aside.
In a medium bowl, whisk together cornstarch mixture, vanilla essence, banana & peach.
Add the melted butter & stir to combine.
In another large bowl, combine together flour, sugar, baking powder, baking soda, cinnamon & salt.
Add the wet ingredients to the dry ingredients and stir only until they are just combined. Overmixing the batter results in tough muffins.
Divide the batter evenly in cups and bake for about 20 mins. Transfer to wire rack to cool completely.