Preheat oven to 180 degrees Celsius (350 degrees Fahrenheit).
Peel the bananas and place in a wide-bottomed bowl, then use a fork to mash until you get a smooth paste.
Place the coconut oil in a separate large bowl and melt over a saucepan of boiling water or in the microwave (skip this step if using any other oil).
Once melted, add the maple syrup to the same bowl along with the vinegar, cinnamon, vanilla, raisins and ground almonds.
Sift in the flour, baking powder and bicarbonate of soda.
Add the mashed bananas, and mix well, adding the milk a small amount at a time until you get a loose batter. You may not need to use it all depending on how liquidy your bananas are - you may also need to add a little more milk if your bananas are dry.
Transfer mixture into a greased baking tin lined with baking paper (I used an 18cm/7inch springform baking tin).
Bake in oven for around 30 minutes until risen and golden brown and an inserted skewer comes out clean.
Once out the oven, leave to cool on a wire rack before applying the frosting.