Preheat oven to 350° F. Spray a 2 - 3 quart or 9" by 13" ovenproof casserole dish with canola oil or grease the dish with butter.
In a large pot bring heavily salted water to a rolling boil. How salty? As Samin Nosrat, author of Salt, Fat, Acid, Heat describes, "until it's as salty as the sea." Pretty salty. This will infuse the macaroni with a good level of saltiness that will be put to good use when tossed with milk, eggs and cheese. Add the macaroni to this boiling water and cook until barely al dente, or just until the macaroni is firm but you can press it in with your finger when you sample one. This will take about 5 - 6 minutes.
Pour the macaroni into a colander and drain well. When drained, pour 1/4 of the macaroni into the bottom of the casserole dish and distribute a several squares of cheese on top.
Toss the nutmeg, smoked paprika and onion powder into the shredded cheese.
Place in 350° F oven and bake for 20 to 30 minutes, until the edges are bubbly and top just begins to brown. Remove from oven and add crumb topping.