Bring a large pot of lightly salted water to a boil. Add the oil and the pasta and cook for 8 to 10 minutes or until al dente; drain well and return to cooking pot.
In a small saucepan over medium heat, melt 8 tablespoons butter; stir into the pasta.
In a large bowl, combine the shredded cheeses and mix well.
Preheat oven to 350 degrees F (175 degrees C).
Add the half and half, 1 1/2 cups of cheese mixture, cubed processed cheese food, and eggs to macaroni; mix together and season with salt and pepper. Transfer to a lightly greased deep 2 1/2 quart casserole dish. Sprinkle with the remaining 1/2 cup of cheese mixture and 1 tablespoon of butter.
Bake in preheated oven for 25 minutes or until hot and bubbling around the edges; serve.