Prep the slow cooker: Line your slow cooker with aluminum foil or a slow cooker liner for easy removal. Grease the liner well with vegetable oil or butter.

Mix wet ingredients: In a large mixing bowl, mash the ripe bananas well to measure 1 cup. Stir in the brown sugar, granulated sugar, egg, vanilla extract, and oil until just combined. The mixture will be thick and slightly lumpy.

Combine dry ingredients: In a separate smaller bowl, whisk together the flour, baking soda, salt, and 1/2 teaspoon of cinnamon.

Combine everything: Gently fold the dry ingredients into the wet ingredients using a rubber spatula. Mix only until the flour streaks disappear. Do not overmix.

Pour into slow cooker: Transfer the batter into the prepared slow cooker. Spread evenly.

Cook: Cover and cook on low for 4 hours, or until the edges are set and a toothpick inserted in the center comes out with moist crumbs (the center may still be slightly soft due to condensation) . Do not lift the lid during cooking to avoid heat loss.

Prepare the topping: In a small bowl, combine the remaining sugar and the additional teaspoon of cinnamon. Melt the 2 tablespoons of butter.

Top the bread: Carefully remove the bread from the slow cooker using the liner. Brush the top with melted butter and generously sprinkle the cinnamon sugar mixture over it. Let cool for 10-15 minutes, then cut into 12 muffin-sized pieces.

Serve: Serve warm or at room temperature. These hold their moisture remarkably well.