Classic Lasagna Bolognese

Directions

1. To make the besciamella, heat the butter in a saucepan over low heat. Add the onion and cook, stirring frequently, until the onion is tender but has no brown color, about 5 minutes. Add the flour and cook, stirring frequently, until the mixture is a golden brown color and it has a rich, nutty aroma, about 6 minutes.
2. Add the milk and the bay leaf and stir well with a whisk to break up any lumps and smooth the sauce. Stir the sauce constantly with a wooden spoon as it returns to a simmer.
3. Once simmering, lower the heat slightly and continue to cook until the sauce is thickened and creamy, 10 to 15 minutes. Taste the sauce and season it to taste with salt and pepper, and nutmeg. Strain through a fine-mesh sieve and reserve. (You may make the sauce up to 3 days in advance. After straining it, let it cool completely, then store in a covered container in the refrigerator. Warm the sauce over very low heat or in a microwave when you are ready to assemble the dish.)
4. To make the pasta dough, mound the flour on a clean surface or put it in the bowl of a stand mixer fitted with a dough hook. Create a well in the center and place the eggs and oil in the center. Using a fork, whisk the eggs and slowly start dragging the flour into the egg mixture. Knead well by hand or with the mixer until all the ingredients are well combined and the dough seems smooth and elastic (about 10 minutes if working by hand, about 5 minutes in a mixer with a dough hook). Wrap the dough in plastic wrap or place it in a covered bowl and let it rest at room temperature for at least 30 minutes.
5. Set up a pasta machine and set it to the largest opening. Dust a work surface with flour. Cut off pieces of dough about the size of an egg. Working with one piece of dough at a time, roll the dough into sheets about 1/8-inch thick.
6. Cut the sheets into noodles that are about 5 inches wide and as long as your lasagna pan (usually about 10 inches) and reserve them on a baking sheet.
7. Bring a large pot of generously salted water to a boil. Add the noodles all at once and stir a few times to separate them. Cook uncovered at a gentle boil until the noodles are just cooked through, 3 to 4 minutes.
8. Drain the pasta immediately through a colander. Shake well to remove any water clinging to the pasta. Immediately rinse the pasta under cold running water until the pasta feels cool. Drain in the colander, and then set the noodles flat on a clean cloth towel or several layers of paper towels to dry completely.
9. Preheat the oven to 350°F. Brush a lasagna pan or baking dish (about 3-quart capacity) liberally with butter or oil. Layer the lasagna in the following order: 3/4 cup besciamella spread into an even layer, topped with lasagna noodles (lay them into the pan so that they very slightly overlap each other), another 3/4 cup besciamella, 3/4 cup Bolognese sauce, and 1/3 cup cheese. Repeat this sequence 3 more times. Spoon the remaining besciamella sauce over the lasagna to make a top layer. Spread it evenly to make sure that the noodles are coated. Spoon the remaining Bolognese sauce on top of the besciamella and sprinkle with the remaining cheese.
10. Bake the lasagna until it is very hot all the way through and a rich, golden crust forms, 40 to 45 minutes. Let the lasagna rest for at least 15 minutes before cutting into pieces and serving.