Hands down the best Mac and Cheese I have ever had! First few times I used regular salt and finally realized it said seasoned salt, believe me seasoned salt makes all the difference in the world! I'll be honest, I add more cheese than called for and use a little more seasoned salt and pepper. More Cheesey goodness right?? LOL!!
Preheat oven to 350 degrees. Lightly butter a deep 2 1/2 quart casserole dish.
Bring a 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 the the cooking pot.
In a small saucepan, melt the 8 tablespoons of butter. Stir into the macaroni. In a large bowl, mix all of the shredded cheeses. To the macaroni, add the half and half, 1 1/2 cups of the shredded cheeses, the cubed Velveeta and the eggs. Season with the salt and pepper. Mix well.
Transfer to the buttered casserole dish. Sprinkle with the remaining 1/2 cup of shredded cheeses and dot with the remaining 1 tablespoon of butter.
Bake in preheated oven until it's bubbling around the edges, about 35-40 minutes. Serve hot.