Preheat the oven to 350°F (176°C). Coat an 8-inch (20 cm) square baking pan with nonstick spray and set aside.
In a bowl, whisk together the cream, pumpkin, milk, sugar, eggs, salt, and spices until well combined.
Toss the bread cubes with butter in another bowl, then pour them into the baking pan. Pour the pumpkin mixture evenly over the bread, pressing it gently into the mixture. Allow it to sit for 15 minutes.
Bake until the custard sets, about 35 to 40 minutes. Allow to cool before serving.
Notes
For added crunch, add your favorite chopped nuts. Walnuts work well with pumpkin.