Brown Sugar Banana French Toast Casserole

Ingredients :

Brown sugar banana filling:
6 tablespoons unsalted butter
¾ cup light brown sugar packed
2 tablespoons pure maple syrup
pinch salt
3 ripe-firm bananas peeled and sliced

French toast:
8 large eggs
1 cup milk preferably whole or 2%
1 cup half and half
2 tablespoons light brown sugar
1 teaspoon ground cinnamon
1 tablespoon pure vanilla extract
One 15 oz loaf French bread cut into large cubes (preferably a day or two old)