Step 1

Preheat oven to 350°F. Lightly coat a 3-quart casserole dish or 9x13 pan with butter or spray with cooking spray.

Step 2

Cook macaroni according to package directions, adding 2 minutes to the maximum time listed on the package. Drain; stir butter into macaroni until butter is melted.

Step 3

While macaroni is boiling, shred both cheese blocks using a box grater. Combine shredded cheese until evenly mix, then set aside about half of shredded cheese mixture for later.

Step 4

In a large bowl, whisk together mascarpone and evaporated milk until smooth (there may still be some lumps, which are okay).

Step 5

Mix in the whole milk, followed by the salt, creole seasoning, mustard powder, and nutmeg. Stir in half of the shredded cheese mixture.

Step 6

Taste mixture to see if seasonings are to your preference and adjust if necessary. Stir in beaten egg.

Step 7

Add buttered macaroni to milk/cheese mixture and stir to combine. Pour the whole mixture into your prepared casserole dish.

Step 8

Sprinkle remaining shredded cheese evenly over the top, followed by some fresh cracked pepper, if you like.

Step 9

Bake in preheated oven for 50 minutes or until cheese on top is melted and browned, and filling is bubbling. Cool slightly before serving.