In a large bowl, whisk together pumpkin, milk, brown sugar, maple syrup, cinnamon, ginger, cardamom, nutmeg, and salt until well blended. Whisk in eggs until smooth.
15 ounces canned pumpkin puree, 1 1/4 cups milk, 1/4 cup brown sugar, 1/4 cup maple syrup, 4 large eggs, 1 teaspoon ground cinnamon, 1/2 teaspoon ground ginger, 1/2 teaspoon ground cardamom, 1/4 teaspoon ground nutmeg, 1/4 teaspoon fine sea salt
Add cubed bread and stir carefully to combine, making sure there are no dry pieces remaining.
8 ounces challah bread
Lightly coat an 8x8 square or 11x7 baking dish with nonstick spray or melted butter. Scoop the bread into the dish, arranging evenly in the pan. Pour any leftover custard over the top. Press down gently to ensure all of the bread is covered.
Cover with plastic wrap and let sit at room temperature for 30 minutes, or in the refrigerator overnight.
When ready to bake, preheat oven to 350°F. Remove plastic wrap and bake for 35-40 minutes.
Let cool for 10-15 minutes (it will deflate slightly) and serve with whipped cream, caramel sauce, or your favorite toppings.