Mario Batali's Cavatelli and Sausage Pie

This was on The Chew and it was absolutely awesome--the only this I changed was opting not to use the Puff Pastry crust topping as it already was enough for me with the pasta. Doesn't the picture just make you want to dig in with a serving spoon!

For the Filling:

Olive Oil 

2 pound Hot Italian Sausage (removed from casing) 

2 medium Onions (finely chopped) 

1 Carrot (finely chopped) 

4 stalks Celery (finely chopped) 

Salt and Pepper to taste 

5 Garlic cloves (sliced) 

1 teaspoon fresh Thyme Leaves

1/8 teaspoon freshly grated Nutmeg 

2 cups Red Wine 

1 16-ounce can Whole Peeled Tomatoes (drained and crushed) 

1 pound Cavatelli

1/2 cup Parmigiano-Reggiano (plus more for grating)

1 recipe of Besciamella

For the Besciamella

5 tablespoons butter

4 tablespoons flour

3 cups milk

2 teaspoons salt

1/2 teaspoon freshly grated nutmeg

In a medium saucepan, heat butter until melted. Add flour and stir until smooth. Over medium heat, cook until light golden brown, about 6 to 7 minutes.
Meanwhile, heat milk in separate pan until just about to boil. Add milk to butter mixture 1 cup at a time, whisking continuously until very smooth and bring to a boil. Cook 30 seconds and remove from heat. Season with salt and nutmeg and set aside.

For the Pie:

1 package Puff Pastry (thawed)

1 Egg plus 1 tablespoon Heavy Cream (beaten)

flaky Sea Salt and Pepper

For the Filling: In a heavy bottomed pot, add 3 tablespoons of olive oil and add the sausage. Brown for 6 to 8 minutes, or until all the sausage is golden. Remove from the pan and set aside
For the Red Sauce:
In a separate pan Add in the onion, carrot, celery, season with salt and pepper, and cook for 5 minutes, until just beginning to soften. Add the garlic and thyme leaves, grate in the nutmeg, and cook for 30 seconds. Deglaze with the wine, scraping up any brown bits on the bottom of the pan with a wooden spoon. Cook for 2 to 3 minutes and then add the tomatoes. Season again with salt and pepper and cook for about 4 to 5 minutes, or until the sauce is thick and the flavors have melded.

Preheat an oven to 350 degrees F. Bring a large pot of water to a boil over high heat and season the water generously with salt. Cook the pasta 2 minutes less than the packaged instructions.

Toss the pasta in with the red sauce. Pour into a casserole 9x9 dish. Stir the Parmigiano into the besciamella, and then pour over the top of the casserole. Grate more Parmigiano and nutmeg on top

This is the part I omitted
For the Pie: Cover with a piece of puff pastry, brush with the egg mixture, and then season the top with salt and pepper. Cook for 15 to 20 minutes, or until the puff pastry is puffed and golden. Let cool for 5 minutes and then serve with freshly grated Parmigiano.