Chicken tortellini is a delicious combination of cheese-filled tortellini, tender bites of chicken, and fresh broccoli tossed in a cheesy sauce and baked until hot and bubbly. This easy casserole is comforting, flavorful, and filling.
CASSEROLE: Preheat the oven to 375 degrees. Cut the broccoli into small pieces (no need to cook beforehand if you chop it small). Chop the chicken into small pieces. Add both to the bottom of a 9 x 13 ceramic baking dish. Add the frozen (not thawed and not cooked) tortellini right on top. Toss everything to combine.
SAUCE: Melt 3 tablespoons butter in a small pot over medium heat. Once melted, gradually add in flour while whisking constantly until a thick paste forms. Whisk for one minute to cook out the raw flour taste and then gradually add in 1/3 cup of the milk while whisking constantly. Gradually add 1/3 cup chicken stock or broth while whisking constantly. Add in another 1/3 cup milk, another 1/3 cup stock, last remaining 1/3 cup milk, and last remaining 1/3 cup stock. Whisk after each addition until completely smooth and sauce is thickened. Add in 1 cup of sharp cheddar cheese and 1/2 cup Parmesan cheese and whisk until completely smooth. Add in sour cream and whisk until smooth. Stir in the chicken bouillon powder, Dijon mustard, dried parsley, garlic powder, granulated onion, and salt and pepper to taste (I add 1/2 teaspoon salt and 1/4 teaspoon pepper; add to taste preference -- the Parmesan cheese does add a good amount of saltiness as well).
ASSEMBLE AND BAKE: Pour the sauce over everything in the casserole dish and toss ingredients to evenly coat. Make sure the tortellinis are generally all submerged in the sauce. Sprinkle remaining 1/2 cup Parmesan cheese over top of the casserole. Cover with foil and bake for 30 minutes. Meanwhile, in a saucepan over medium high heat, melt the 2 tablespoons butter for the topping. Add the Panko and toast, stirring constantly, until Panko is a light brown and toasted. Once casserole has baked for 30 minutes, remove and then sprinkle topping evenly over cheese. Bake, uncovered, for another 8-10 minutes or until warm and bubbly. Remove and serve hot.