1Preheat oven to 350 degrees F. Lightly butter a 2 1/2 quart casserole dish. Set aside.
2Bring 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 mins. Do not overccok. Drain well. Return to the cooking pot.
In a small saucepan, melt 8 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 shredded Cheese, the cubed Velveeta and the eggs. Season with the Seasoned salt and pepper. Transfer into the buttered casserole dish. Sprinkle with the remaining 1/2 cup of shredded cheeses and dot with the 1 tablespoon of butter.
Bake until its bubbly around the edges, about 35 mins. Serve hot.