01 -
From each of the shredded cheddar, colby jack, gouda, and gruyere cheeses, set aside 1/2 cup in total and combine for the topping.
02 -
Preheat oven to 350°F. Brush a 9 by 13 by 3-inch baking dish with melted butter or coat with non-stick spray.
03 -
Bring approximately 17 cups water to a boil in a large pot. Add kosher salt, then stir in the elbow macaroni. Cook for about 10 minutes until just tender. Drain thoroughly.
04 -
In a bowl, whisk together the beaten egg, evaporated milk, seasoned salt, granulated garlic, granulated onion, ground mustard, paprika, black pepper, and cayenne pepper until smooth.
05 -
Return cooked macaroni to the pot. Melt butter over medium heat and toss with the pasta. Pour in the egg and spice mixture, stirring to combine evenly.
06 -
Add the remaining shredded Velveeta, cheddar, gouda, gruyere, and colby jack cheeses to the pot. Mix well; some pieces may remain partially melted.
07 -
Spoon the macaroni and cheese mixture into the prepared baking dish. Evenly distribute the reserved shredded cheeses over the top.
08 -
Cover the dish tightly with foil sprayed on the inside with non-stick spray. Bake for 30 minutes.
09 -
Remove the foil. Continue baking uncovered for 25 to 30 minutes, or until the top is golden and bubbling. Let the casserole rest for 10 minutes before serving.