Preheat your oven to 330 degrees. In a medium pot add the milk and bring to a simmer. While the milk is simmering cut up the extra sharp cheddar cheese into squares.
Bring a large pot of water to a boil. Once the water is boiling add salt and then your macaroni. Cook for about 8-9 minutes stir frequently.
Once the milk starts to warm add the cheddar cheese to the milk. Season with salt and pepper. Continue to stir the milk and cheese mixture, checking to see if the cheddar cheese has melted.
Whisk an egg in a small bowl add a pinch of pepper to the beaten egg, whisk, then pour the egg into the milk mixture. Continue to stir the milk mixture to make sure it doesn't burn and stick to the bottom of the pan.
At this point the cheddar cheese should be melted, add the last of the taco cheese to the milk mixture and let simmer for a few minutes then turn off the flame. Drain the macaroni well and add to a baking dish. Add the butter and pepper to the macaroni and coat evenly. Pour the milk mixture over the macaroni and mix until every piece is covered. Bake for about 20 to 30 minutes or until the macaroni turns a light brown.