Stir the graham cracker crumbs and melted butter together until evenly moistened, then press the mixture firmly into the bottom of a small loaf pan or baking dish that fits inside your slow cooker.

Beat the cream cheese and granulated sugar until smooth, then mix in the egg and vanilla extract until just combined. Pour the filling over the crust and smooth the top.

Place the pan inside the slow cooker and add enough hot water to come halfway up the sides of the pan. Cover and cook on low for 2 hours, until the center is set but still slightly jiggly.

Turn off the slow cooker, remove the pan, and let the cheesecake cool to room temperature before chilling for at least 2 hours.

When ready to serve, melt the remaining butter in a skillet over medium heat. Add the brown sugar, cinnamon, and sliced bananas, then cook for 2 minutes until the bananas soften. Carefully pour in the rum and cook for 1 more minute to reduce slightly.

Spoon the warm bananas Foster mixture over the chilled cheesecake and cut into bars.