Chicken Alfredo Stuffed Shells

Grab a mixing bowl and to it add your chicken, olive oil, onion powder, garlic powder, paprika, Italian seasoning, crushed red pepper flakes, and 1 tsp of kosher salt. Stir together until all of the chicken is coated in the oil and the seasonings are distributed throughout. Allow the chicken to marinate for 15-20 minutes at room temperature, or up to overnight in the fridge.
Preheat your oven to 375°F and place an oven rack smack dab in the center. Grease a baking dish – at least 9×13 – lightly with baking spray or oil and set it aside. Prepare the salted water to boil your noodles in.
Place a large non-stick skillet or saucepan over medium-high heat and allow to preheat for 2 minutes. If it’s not completely nonstick feel free to add a drizzle of olive oil, just enough to cover the surface. Add the chicken in a single layer – go in batches, if needed – and let cook undisturbed for 5 minutes, then give it a stir and toss it around so the sides of the chicken that haven’t made contact with the pan get some action. Cook until the chicken is cooked through, about 3-5 minutes more. Set the chicken aside to rest while you make the pasta and sauce. 
To the same pan you cooked the chicken in, add the butter. Reduce the heat to medium-low and allow the butter to melt. When it has, whisk in the grated parmesan and half-and-half. Stir in the black pepper. Let the sauce simmer uncovered, for about 10-15 minutes, stirring occasionally.
The water you prepared earlier should be boiling by now, so while the alfredo sauce is cooking, add the pasta. Cook for 5 minutes, then add the broccoli. Cook together until the pasta is al dente and the broccoli becomes an intense, bright green, then use a strainer to remove the broccoli from the water and add it to the bowl of cooked chicken, making sure to let the excess water drip off into the pot first. Drain the pasta shells – don’t forget to reserve some water! – and set them aside, as well (you can leave them in the pot they cooked in). 
The sauce should have thickened and reduced just a tad by now. Give it a stir, then whisk the pasta water into the sauce. Give it a taste, and add salt or adjust for seasonings as you see fit, then turn off the heat and replace the lid. 
While you wait for the shells to become cool enough to handle, work on the filling. To the bowl of chicken and broccoli, add 1 cup of mozzarella and 2 cups of the hot alfredo sauce. Use a wooden spoon to stir it all together, until the cheese has melted and everything is well distributed. Grab your baking dish and ladle about half a cup of alfredo sauce into the bottom of the pan. Spread it around. 
Now it’s time to stuff! I use my hands and a spoon, holding the shell open in my hands and using the tip of the spoon to force it in. Some folks use a piping bag – or a Ziploc bag when the end cut off – to squeeze it in. Overfill them just a little so that the shells stay open and the filling is visible. Place them side by side, squeezing them in together (not too tight) so they remain stable and upright. Continue until something runs out, or the pan is full.
Now, ladle the remaining sauce over the tops of all the shells. Once that’s finished, cover everything with the remaining mozzarella, evenly. You can add extra cheese if you want full coverage. I finish with little bits from the bottom of the bowl of broccoli and finishing pepper for garnish. 
Place the shells in the oven for 30 minutes, or until the top has turned golden brown and the edges are bubbling. Let rest for about 10 minutes before serving, and enjoy. Dassit!