Preheat oven to 350 degrees. Spray an 8x8 baking dish with cooking spray. 

In a food processor add the plantains and coconut oil and collagen powder if using. Process for 1-2 minutes or until batter is fluffy and all chunks are mixed in.  

Pour batter into the prepared 8x8 baking dish. Place in the oven and bake for 25 minutes.

In a small saucepan over low heat, add the frozen strawberries. Stirring occasionally, cook for 15 minutes or until strawberries have reduced and are getting thick. Remove from heat. 

Remove cake from oven. Let cool. Cut into 6 slices and serve on a plate, topping with a generous spoonful of reduced strawberries.