Heat oven to 350°F. Grease a 9x13-inch baking dish.
Cut the cinnamon roll dough into 1-inch pieces and scatter evenly in the dish.
Stir together brown sugar, cinnamon, and nutmeg. Sprinkle the mixture over the dough.
Drizzle the melted butter over the sugared dough pieces.
Whisk eggs, milk, cream, vanilla, and salt until smooth. Pour evenly over the pan, tapping to settle.
Scatter pecans on top, if using.
Bake 32–38 minutes, until puffed, golden, and the center is set.
Beat cream cheese and powdered sugar until smooth. Mix in milk and vanilla until pourable.
Cool casserole 10 minutes. Drizzle with glaze and serve warm.