Preheat the oven to 325 degrees F. Spray a 9x13 pan with cooking spray.
Brown the breakfast sausage in a large skillet and cook until no longer pink. Remove from the heat.
Whisk together in a large bowl the sour cream, heavy cream, ground mustard, garlic, salt, pepper, and eggs.
Add the sausage, hash browns, both cheeses, bell pepper, and scallions, reserving 2 tablespoons of the scallions for a garnish.
Unroll the crescent dough and press it into the bottom of the prepared baking dish. Pierce the dough with a fork evenly throughout. Pour over the egg mixture and spread evenly.
Cover with aluminum foil and bake for 40 minutes. Remove the aluminum foil and continue to bake until golden brown and eggs are set (about 20 minutes).
Remove from the oven and let rest 10 minutes before serving. Garnish with reserved scallions.