Preheat your oven to 375°F. Grease a 9×13-inch baking dish with cooking spray and set it aside.
Cook the elbow macaroni according to the package instructions until it is al dente. Drain the cooked macaroni and rinse it under cold water to stop the cooking process. Make sure to let it drain thoroughly.
In a medium saucepan, combine the chunks of Velveeta cheese and milk. Heat this mixture over medium-low heat, stirring frequently until the cheese melts and becomes smooth. Remove the saucepan from heat and set it aside.
In a small bowl, whisk the eggs until they are well beaten. Slowly add a scoop of the warm cheese sauce to the egg mixture, whisking continuously to temper the eggs. Once combined, add this egg mixture back into the remaining cheese sauce in the saucepan, whisking until fully incorporated.
Begin layering! Place half of the cooked macaroni evenly into your prepared baking dish. Sprinkle with salt and pepper to your liking. Place thin slices of butter over the macaroni. Then, sprinkle half of the shredded Cheddar and Monterey Jack cheeses over it. Pour half of the cheese sauce on top.
Repeat the layering process with the remaining macaroni, seasoning, butter, shredded cheeses, and cheese sauce.
Bake your mac and cheese uncovered in the preheated oven for 30-35 minutes, or until it is bubbly and the top is lightly browned.
Let the baked mac and cheese cool for a few moments before serving. Enjoy this creamy, cheesy delight!