I start by heating oil in a heavy skillet or Dutch oven over medium heat. Once hot, I brown the ground beef with salt and pepper, breaking it into small pieces.
Then I stir in garlic, dried herbs, water, and crushed tomatoes, let it come to a gentle boil, cover, and let it simmer for about 30 minutes so flavors meld. At the end, I taste and adjust with sugar, salt, pepper until everything is balanced.
While the ragu simmers, I melt butter in another saucepan over medium heat. I whisk in flour and cook it for a few minutes until it’s lightly golden.
Then I slowly add milk (first a cup while whisking vigorously, then the rest) on medium-low heat until it thickens and becomes smooth. I finish by adding nutmeg, and if I needed more salt if butter was unsalted.
I bring a large pot of well-salted water to a rolling boil, put in the dried lasagna noodles, and stir gently so they don’t stick. Once they’re cooked according to package directions, I drain them and lay them flat on a baking sheet so they don’t clump together.
First, I preheat the oven to 325°F (about 165°C). I oil or spray the baking dish lightly. Then I spread a thin layer of ragu (just enough so the noodles don’t stick but the bottom still shows). I add noodles, béchamel, a sprinkle of Parmigiano, then another layer of ragu. I keep layering until ingredients are used, finishing with noodles, béchamel, and cheese on top. I cover the dish tightly with foil, bake it for about 1 hour. After that, remove foil, increase heat to around 400°F (200°C), and bake for another 10-15 minutes so edges get golden and cheesy. Let it rest about 10 minutes before cutting so it sets.