Make the strawberry reduction: Blend the strawberries then pour the blended strawberries into a saucepan on a low to medium heat. While the strawberries are reducing, ensure you continue to stir. The strawberries will start to bubble and you may see paler pink water on top. Continue stirring until the strawberries have reduced to around half and you can no longer see the pale pink water on top. This should take around 15 minutes but may take longer depending on how much water is in the strawberries. The strawberry sauce should now be thicker. Pour the strawberry sauce into a bowl and set aside to cool completely before use.
Once the strawberry reduction has cooled, preheat the oven to gas mark 4/350oF/180oC and line a 8 or 9 ich baking tin with baking paper.
Make the cake: In a bowl prepare the dry ingredients by adding the self-raising flour, bicarbonate soda and salt then whisk and set aside. Blend together the bananas and milk and if using food colouring, add it to the blended bananas. Set aside.
In a mixing bowl, mix the butter and sugar until light and fluffy then add the vegetable oil and continue to combine.
Add the egg yolk, sour cream and vanilla extract then combine until they are all fully incorporated. Mix in the blended bananas and the strawberry reduction then mix in the dry ingredients.
Whisk the egg whites for around 5 minutes or until soft peaks are formed then gently fold them into the cake batter.
Once the egg whites are combined, pour the batter into the cake tin and bake for around 50 minutes or until a cake tester comes out clean. Onced baked allow to cool for 15 minutes before transferring to a cooling rack to completely cool.
Make the whipped cream frosting: Add the double cream and icing sugar to a stand bowl mixer or mixing bowl and whisk on a medium speed or until stiff peaks are formed. Be careful not to over whip the cream as it will turn into butter. Frost the cake with the whipped cream, decorate with the bananas and strawberries then enjoy.