Butter 4 ramekin bowls. Preheat oven to 375 degrees F.
Bring a large pot of water with 1 tablespoon of salt to a boil. Add pasta and stir just until water returns to a boil. Cook until just al dente, drain, shaking well. Meanwhile, beat egg whites to stiff peaks with an electric hand mixer.
To begin making cheese sauce (steps 3 - 5), melt butter in a large saucepan over medium-low heat. Add onion and cook until softened. Sprinkle flour over onion and stir constantly for 2 minutes. Don’t allow flour to brown. Add 1 cup of milk a little at a time, stirring constantly. Stir until smooth, then add bay leaf, thyme, peppercorns, remaining 2 teaspoons of salt, and 2 ½ cups of milk.
Increase heat to medium-high and continue stirring frequently until liquid reaches a boil. Don’t let it boil over. Boil for 1 minute, then reduce heat to low so milk barely simmers, and continue to cook, stirring frequently, for 10 minutes more.
Remove from heat and let stand for 5 minutes, and then strain through a sieve into a very large bowl, working onions back and forth with a rubber spatula to extract all the liquid possible. Immediately stir in plenty of pepper, the nutmeg, and all cheeses, stirring until just melted.
Stir cooked macaroni into the cheese mixture, then fold in beaten egg whites. Spoon mixture into ramekins, mounding slightly, and top each with a big pinch of bread crumbs.
Bake for 25 – 30 minutes, until cheese is quietly sizzling and bread crumbs are golden. Let cool for 5 minutes, drizzle with truffle oil, and serve.
GARLIC BREAD CRUMBS
Country-style white bread, crusts removed (about 3 thick slices)
Large garlic cloves, minced or pushed through a garlic press
Freshly ground black pepper
2 ½ tbsp.
Extra virgin olive oil
Pulse bread in a food processor until it becomes coarse crumbs.
Toss crumbs with garlic, salt, and pepper in a large mixing bowl until thoroughly combined. Add olive oil and work vigorously with a rubber spatula to force oil into crumbs.