Lightly spray a casserole dish with cooking spray or add a teaspoon of oil with the fish pieces. Bake at 350 for about 15 minutes, flipping once and cooking until the fish flakes easily.
While fish bakes, cook pasta according to package directions.
Make the sauce by whisking the cornstarch, paprika, salt and pepper to taste into the milk. Bring to a boil over medium heat, stirring constantly until thickened. whisk in cheeses until melted.
Add salmon and drained pasta and bake uncovered at 350 until thoroughly heated and sauce thickens a bit more.
Recipe by Cindy's Recipes and Writings at https://www.cindysrecipesandwritings.com/salmon-mac-and-cheese/