For the casserole:
1 (16-ounce) loaf brioche, cut into 1-inch pieces
Cooking spray or unsalted butter
6 large eggs
2 cups half-and-half
1 (14-ounce) can pumpkin purée
3 tablespoons granulated sugar
1 tablespoon pumpkin pie spice
1 teaspoon pure vanilla extract
1/4 teaspoon kosher salt
Powdered sugar, for serving (optional)
Maple syrup, for serving (optional)
For the crumb topping:
1/4 cup all-purpose flour
3 tablespoons packed light brown sugar
3 tablespoons chopped, toasted pecans
1/2 teaspoon ground cinnamon
1/2 teaspoon ground nutmeg
Pinch kosher salt
2 tablespoons unsalted butter, melted