Preheat the oven to 300°F (150°C). Arrange the slices of challah bread on a wire rack set atop a rimmed baking sheet. Bake for approximately 16 minutes, flipping each slice halfway through, until the bread is nearly dry throughout. Remove from the oven and allow to cool for 5 minutes. Reduce the oven temperature to 200°F (95°C) to keep the French toast warm later.

In a large mixing bowl, whisk together the eggs, heavy cream, and cinnamon until well combined. Pour the custard mixture into a 9 x 13-inch shallow baking dish to facilitate soaking.

Carefully submerge each slice of challah in the custard for about 20 seconds per side, ensuring the bread is saturated but still intact. Using a slotted spatula, lift each slice, allowing the excess custard to drip off, and place it on a clean tray or baking sheet.

Preheat an electric griddle (or large non-stick skillet) to 350°F (175°C). Lightly coat the surface with non-stick cooking spray or melt butter to prevent sticking. Transfer the soaked slices to the griddle and cook for 3 to 4 minutes per side, or until golden brown. Transfer the cooked slices to a baking sheet and place in the warm oven while cooking the remaining slices.

In a large skillet over medium-high heat, combine the corn syrup, brown sugar, maple syrup, and chopped pecans. Stir and bring to a gentle boil. Reduce heat to medium-low and allow the mixture to simmer for 2 minutes. Carefully add the halved bananas and the rum extract, stirring gently to coat the bananas in the syrup. Simmer for an additional minute, taking care not to overcook the bananas.

Arrange the warm French toast slices on serving plates. Spoon the banana-pecan syrup generously over each portion. Serve immediately for best texture and flavor.