In a large pot, cook the pasta in boiling water until al dente. Drain the pasta and set it aside.
In the same pot, melt the butter over medium heat. Add the flour and whisk for about 1 minute to form a smooth paste.
Mix in the dry mustard powder, onion powder, garlic powder, salt, and black pepper. Gradually whisk in the chicken broth and continue stirring over medium heat until the sauce begins to thicken, about 3 to 4 minutes.
Stir in the half-and-half and cook for an additional 2 minutes while stirring constantly. Remove the pot from the heat.
Slowly stir in the shredded cheddar cheese and Parmesan until melted. Gently mix in the pasta and tuna until evenly coated.
Serve the Tuna Helper hot. For a pop of color and extra flavor, you can garnish with chopped fresh parsley if desired.