For the stuffing: Preheat the oven to 350 degrees F. Add the butter to a large saute pan and allow to melt over medium heat. Once melted, add the onions, carrots and celery. Season with salt, pepper and red pepper flakes and stir to combine. Allow the vegetables to saute until softened, 3 to 5 minutes. Add the sausage, sprinkle again with salt and pepper and break up the sausage with a wooden spoon while it browns, 7 to 10 minutes. Once the sausage is cooked through, turn off the heat.
While the sausage is cooking, prepare the stove top stuffing according to package directions. Turn off the heat and set aside to cool slightly.
Spray a bundt pan with cooking spray and set aside.
Add the stuffing to a large bowl. Add the sauteed veg and the lightly beaten eggs to the stuffing and toss to combine. Evenly pour the stuffing into the prepared pan and press down.
Bake until browned on top, 25 to 30 minutes. Remove from the oven and set aside to cool briefly.
For the creamy mashed potatoes: Add the potatoes to a pot and cover with water. Season with salt and turn the heat to high. Once the potatoes come to a boil, cook until fork tender, about 10 minutes. Drain and pass the potatoes through a potato ricer into a bowl. Stir in some of the heated cream until the consistency is thick, creamy and pourable, adding cream as needed. Season with salt and pepper and stir in the butter.
For the cranberry sauce: Add the cranberries, sugar, orange zest and orange juice to a saucepan. Turn the heat to medium and cook until the cranberries have burst and the sauce thickens, about 20 minutes. Season with salt, remove from the heat, strain and set aside.
To serve: Loosen the stuffing from the sides of the pan with a butter knife. Top the pan with a cake stand and flip to invert. Remove the pan. Garnish with the creamy mashed potatoes, cranberry sauce, fried onions and chives. Slice, plate and drizzle with gravy.