Preheat the oven to 350°F. Either line your cake pan with parchment paper or grease it thoroughly with oil or butter.
In a bowl, cream together the butter and sugar, whipping it with the electric mixer on medium for 1-2 minutes. Then add your mashed banana and mix again for 30 seconds until combined. Add the canola oil, vanilla extract and 2 eggs, and beat until combined, another 1-2 minutes.
Add in the flour, baking soda, baking powder, salt and cinnamon and and beat together on low for 1 minute, until the batter comes together and no lumps remain. At this point, the batter should appear a bit thick. Add in the coconut milk and mix until the batter has loosened. If it still isn't a runny consistency, add some more coconut milk.
Gently fold in the shredded coconut (optional) with a spatula.
Pour the batter into the prepared pan and bake for 20-23 minutes, until slightly golden brown. A knife should come out clean when inserted. Set aside to cool.
In the meantime, make the frosting. In a clean bowl, beat the butter until soft and whipped, about 1 minute. Add in the powdered sugar and beat for an additional minute. The frosting should start to thicken. Add in the cinnamon, cream cheese and vanilla extract and beat on low until the mixture is thick and fully combined.
Remove the cake from the pan and frost it. Enjoy!