Start by boiling a large pot of salted water. Add the macaroni and cook according to package instructions until al dente. Drain the pasta in a colander and set it aside.
In a large mixing bowl, combine the alfredo sauce, evaporated milk, grated sharp cheddar cheese, and gouda cheese. Stir until well blended. Add more evaporated milk if you prefer a creamier consistency.
Add the drained pimentos, pepper, and seasoning salt to the cheese mixture. Mix thoroughly to combine all ingredients well.
Add the cooked macaroni to the cheese mixture. Using a spatula or wooden spoon, gently fold the pasta into the sauce until every piece is coated.
If you prefer a baked version, transfer the mixture into a baking dish. Sprinkle extra cheese on top if desired. Bake at 350°F (175°C) for about 20 minutes or until bubbly and golden on top.
Let the Pimento Mac and Cheese cool for a few minutes. Garnish with dried chives if desired, and serve warm.