Step 1

Preheat the oven to 350 degrees F. Line an 8 x 8 baking pan with parchment paper -- otherwise your cake will likely not come out clean.

Step 2

In a large bowl, stir together the bananas, egg, vanilla, and coconut oil (measured when completely melted). Stir until completely combined.

Step 3

Add in the cornstarch, baking powder baking soda, cinnamon, and allspice if desired.. Stir until completely combined. (Here's where you can increase or decrease spices to personal preference -- if you are wary of too much spice add a little less and if you LOVE spice increase them.)

Step 4

Stir in the brown sugar and oat flour (blend regular old fashioned oats or quick oats in a blender or food processor until they resemble flour -- blend well so you don't have any weird oat chunks! Measure AFTER blending and not before).

Step 5

Stir in chocolate chips or nuts

Step 6

Bake for 25-30 mins at 350 degrees or until a fork when inserted comes out clean. Be careful to not over bake as it will make this cake less tender and less flavorful. Allow to cool.

Step 7

In a microwave safe bowl combine the chocolate chips and milk. Microwave in bursts of 15 seconds, stirring for 15 seconds in between each burst until the chocolate is completely melted.

Step 8

Whisk in the powdered sugar.

Step 9

Start with 3/4 a cup and add as needed. Note that the frosting thickens up a lot after being refrigerated.

Step 10

Refrigerate the frosting (covered in an airtight container) for at least 30 minutes.

Step 11

Cover the completely cooled cake with the frosting.