Preheat oven to 475°F. In a large pot of boiling salted water, cook the macaroni for 6 minutes (will be cooked to al dente). Drain.
Meanwhile, heat a small skillet over medium heat and melt the butter. Add the garlic and cook until fragrant, about 1 minute. With a slotted spoon, remove the garlic to a medium bowl. Add the macaroni to the bowl and stir to combine.
In a large bowl, whisk together the eggs and evaporated milk. Add the salt, cayenne pepper and cheeses; mix well. Add the macaroni mixture and stir well to combine.
Transfer mixture to an 8- or 9-inch square baking dish or 2-quart gratin dish. With a spoon, gently spread mixture to form an even layer. Bake just until sauce bubbles at edges, about 12 minutes. Let rest for 10 minutes before serving.