Yes, you can. The reason I skip it in this recipe is that it adds another pot and another cooking step, but you can 100% make this lasagna with a bechamel sauce. If you do, make your bechamel (my go-to recipe is 2 tablespoons butter, 2 tablespoons flour, 1 cup of milk, 1 cup of cheddar cheese, a little salt, pepper and paprika), then pour it on top of the lasagna after the pasta has cooked in the sauce. Scatter the mozzarella on top and transfer under the broiler.