Slice french bread into cubes. Place in large bowl, and set aside.
Spray a small round baking dish with non-stick baking spray, and set aside.
Cube French bread, and slice the bananas.
Beat cream cheese, maple extract, half the brown sugar and half the granulated sugar together on medium speed for 1 minute or until creamy enough to spread.
Layer bread, then banana slices, cream cheese mixture, bread and bananas, in that order.
Place sliced butter on the top banana layer.
Mix eggs, milk, cinnamon, vanilla and remaining brown and granulated sugar in a mixing bowl. Pour egg mixture over bread and banana layers.
Add 1/2 cup water to the Instant Pot, and add the trivet. Place baking dish in pot on top of trivet.
Place the lid on the pot and make sure the release valve is in the “sealing” position.
Set to HIGH PRESSURE for 25 minutes. Once the 25 minutes is up, turn the steam release valve to "venting."
Let sit for 10 minutes to allow ingredients to settle and firm up.
Place a large plate over the baking dish, and carefully flip it over. Lift the baking dish away from the French toast. Let sit for another 5 minutes. The remaining steps are OPTIONAL if you'd like the caramelized banana garnish.
In a small saute pan, cook sliced bananas, walnuts and maple syrup over medium heat.
Stir often, making sure not to burn.
Top French toast with sauted bananas, walnuts and maple syrup.