Prepare your crockpot by lining it with parchment paper or spraying it with a non-stick spray.
Prepare your cake mix according to the package instructions.
Mix in the mashed banana and cinnamon to the prepared cake batter.
Stir in the pecans.
Pour into prepared crockpot and spread evenly.
Stretch paper towels under the lid when covering so they fit tightly. This will catch extra moisture to prevent a soggy cake.
Cook on high for 2 hours or low for 4 hours. Check your cake 30 minutes before the finishing time to evaluate its doneness. It may need slightly more or less time depending on the slow cooker. You want a toothpick inserted into the center of the cake to come out clean and for the cake to be firm.
Once the cake is baked, unplug the slow cooker and remove the lid to allow the cake to cool. When it has cooled, ice the cake with your favorite frosting.
Slice and enjoy!
For a gluten free cake use a gluten free cake mix.