Begin this recipe the night before you plan to serve it.
In a large mixing bowl, whisk together the pumpkin, brown sugar, Pumpkin Spice Blend, lemon zest, and salt.
Add the eggs and vanilla extract to the bowl and whisk until smooth.
Finally, add the half-and-half and 1 tablespoon of the melted butter to the bowl and whisk everything together until smooth.
Grease the slow cooker's ceramic insert with the rest of the melted butter- alternatively, if you plan to bake this casserole- grease a 9"x13"x3" casserole dish.
Add half of the cubed brioche and half of the cream cheese chunks to the dish. Cover with the remaining bread and the rest of the cream cheese.
Pour the pumpkin custard over the bread and cream cheese. Use a large spoon to stir the casserole before covering the dish and refrigerating the casserole for 8 hours (or a minimum of 4 hours).
After soaking, bring the ceramic dish to a warmer temperature by allowing it to sit on the counter for a half-hour. This important step reduces the chance of that ceramic insert shattering due to a drastic change in temperature.
Cook the casserole for 2 hours on high or until the casserole's internal temperature reads 165°F.
Spoon the casserole onto individual plates or bowls, and sprinkle with a generous amount of powdered sugar, a drizzle of maple syrup, or a combination of the two.
Enjoy soon after serving.
Store leftovers in a container in the refrigerator for up to 2 days, or frozen for up to 2 months.
add the stir-ins when layering the bread and cream cheese
When baking this Pumpkin Cream Cheese French Toast casserole in the oven:
To serve refrigerated leftovers: reheat in the microwave until warmed through.
For the frozen leftovers: thaw completely under refrigeration before reheating thoroughly in the microwave.