Preheat oven to 375°F (190°C). Grease a 9x13 inch casserole dish with cooking spray.

Cook rigatoni pasta according to package directions until al dente. Drain and set aside.

Heat vegetable oil in a skillet over medium heat. Add sliced turkey sausage and cook for 5 minutes per side until browned. Remove sausage and set aside.

Add sliced mushrooms and diced onion to the skillet. Cook for 5 minutes until softened, stirring occasionally.

Melt butter in the skillet. Sprinkle in all-purpose flour and cook for 1 minute, stirring constantly.

Gradually whisk in milk until smooth. Bring to a simmer and cook for 2 minutes, stirring, until thickened. Stir in salt.

Add the cooked pasta, browned sausage, and chopped kale to the sauce. Stir to combine.

Pour the mixture into the prepared casserole dish. Top with shredded cheese and bake for 20-25 minutes, or until bubbly and golden brown.