Three Cheese Mac and Cheese

I made this last week and I am sad because the leftovers are almost gone. It was delicious!

1 (16 ounce) package elbow macaroni (I used 8 oz of macaroni)
2 eggs
1 (12 ounce) can evaporated milk
1/4 cup butter, melted
2 tablespoons prepared mustard
1 teaspoon seasoned salt (did not use)
1 teaspoon pepper
8 ounces process cheese (Velveeta), melted (about 1/4 of the whole brick)
2 cups shredded mild Cheddar cheese, divided (I used mozzarella)
2 cups shredded sharp Cheddar cheese, divided

I also added chopped red onion

Cook macaroni according to package. In a large bowl, combine eggs, milk, butter, mustard, seasoned salt and pepper and onion (if using). Stir in the melted processed cheese and about 1 1/2 cups of the other cheeses. Drain macaroni and stir into mixture. Pour into a greased pan. Cover with the remaining chesses. (I more than you were supposed too. I like mine to be COVERED in cheese on top.) Bake, uncovered, at 350 for 25-30 minutes or until cheese is melted and edges are bubbly.

This was quite possibly the best macaroni and cheese I have ever had. Seriously.