Preheat oven to 350 degrees and grease a 9-inch pan.
Place the dates and water in a small saucepan, uncovered, over high heat. As soon as the mixture comes to a boil, add the baking soda. Mixture will foam up; reduce the heat to medium or medium high if mixture starts to foam over. After a minute or two, the dates should begin to break down. Use a wooden spoon to stir/mash up the dates a little. Let simmer for another five minutes or so until the dates break down into a paste-like mixture. Add an additional splash of water if the mixture starts to look dry before the dates have completely broken down. Once dates are a stir-able mass, set aside to cool.
In a large bowl, combine the flours, cocoa, baking soda, baking powder and salt. Add the date paste, vanilla, milk, bananas, oil and peanut butter and stir until well combined. Do not overmix. Fold in chocolate chips.
Pour batter into prepared pan and swirl in the cranberry sauce. Bake for 35 minutes. Cake is done when fork comes out relatively clean (aside from melted chocolate) and top springs back lightly when touched.
Serve dusted lightly with powdered sugar, if desired. I'm thinking a melted drizzle of peanut butter on top would also be duh-licious.