1 tablespoon vegetable oil
1 pound elbow macaroni
8 tablespoons (1 stick) plus 1 tablespoon butter
1/2 cup (2 ounces) shredded Muenster cheese
1/2 cup (2 ounces) shredded mild Cheddar cheese
1/2 cup (2 ounces) shredded sharp Cheddar cheese
1/2 cup (2 ounces) shredded Monterey Jack
2 cups half-and-half
1 cup (8 ounces) Velveeta , cut into small cubes
2 large eggs , lightly beaten
1/4 teaspoon seasoned salt
1/8 teaspoon freshly ground black pepper
Preheat the oven to 350 degrees F. Lightly butter a deep 2 1/2-quart casserole.
Bring the large pot of salted water to a boil over high heat. Add the oil, then the elbow macaroni, and cook until the macaroni is just tender, about 7 minutes. Do not overcook. Drain well. Return to the cooking pot.
In a small saucepan, melt eight tablespoons of the butter. Stir into the macaroni. In a large bowl, mix the Muenster, mild and sharp Cheddar, and Monterey Jack cheeses. To the macaroni, add the half-and-half, 1 1/2 cups of the shredded cheese, the cubed Velveeta, and the eggs. Season with salt and pepper. Transfer to the buttered casserole. Sprinkle with the remaining 1/2 cup of shredded cheese and dot with the remaining one tablespoon of butter.
Bake until it's bubbling around the edges, about 35 minutes. Serve hot.