Double Cheese and Macaroni

I had a craving for Macaroni and Cheese and so I started looking up recipes according to what I had on hand, and I found one and modified it. I think it turned out really yummy, actually one of my favorite macaroni and cheese's I've made so far. It's a simple one without crust topping. I served it with meatloaf and thought it complimented it really well. It could be served as a side or a main dish. Sorry I didn't take a picture of the ingredients.

Ingredients
2 cups macaroni, uncooked
1/4 cup butter or margarine
1 1/2 cups cheddar cheese, shredded (I used mild)
1 1/2 cups mozzarella cheese, shredded
2 cups milk
2 egg yolks (or 1 egg, I used egg yolks b/c of Daniel's egg white allergy)
1/2 tsp salt
1/4 tsp pepper

Directions
Boil macaroni according to package directions. Drain, return to pot, and melt butter or margarine in the hot macaroni. In a large bowl, whisk together eggs, milk, salt, pepper, and both cheeses (reserving about 1/2 cup). This is where I might differ a little next time. My cheese kind of grouped in clumps, so I think if I had melted the cheese first, maybe the whisked milk, egg, salt, pepper, and cheese over a stove top, it might have made it smoother. Either way, it was so yummy! Mix everything together and pour into sprayed square baking dish. Top with remaining 1/2 cup cheese and bake at 375 degrees for 30-40 minutes. Let sit to cool and thicken some before serving. I found it was a little soupy, but after cooling and then reheating the next day, it was the right amount of milk.