I made an edit to the Bechamel Sauce. I added grated Parmesan Cheese when it was ready to come off the heat. A wise addition.
Ingredients-
For the Bechamel
3 tablespoons unsalted butter
3 tablespoons all-purpose flour
1 1/2 cups whole milk
Salt
Pinch freshly ground nutmeg
1/4 cup of Parmesan Cheese
For the Lasagna
1/2 package no-boil (or the equivalent in fresh) lasagna sheets
3/4 cup shredded fresh mozzarella
Bolognese Sauce
Method-
Make the bechamel.
In a medium heavy saucepan melt the butter over medium-low heat. Whisk in the flour, and once the mixture starts to bubble cook for another 2 minutes, whisking frequently. Don't let the mixture brown.
Whisk in the milk slowly and raise the heat to bring the mixture to a boil.
Lower the heat and keep whisking until the sauce turns thick and smooth, 2 to 3 minutes.
Remove the bBechamel from the heat, stir in the Parmesan cheese and cover and set aside.
Heat the oven to 350 degrees.
To assemble the lasagna, spread a couple of tablespoons of the bolognese in the bottom of an 8-by-8-inch square baking dish.
Add a layer of lasagna noodles, overlapping them slightly if necessary.
Spread 1/3 of the bechamel evenly over the noodles, and then spread 1/4 of the remaining bolognese over that.
Add another layer of noodles.
Repeat until you have used all of the bechamel.
Add a final layer of noodles and spread the remaining bolognese over the top.
Sprinkle the mozzarella evenly over the top of the lasagna.
Cover the lasagna with a sheet of parchment paper and then wrap the dish tightly in aluminum foil.
Bake for about 40 minutes, until the noodles are just tender (test them by piercing the lasagna with a sharp knife).
Turn the oven up to 425 degrees and remove the foil and the parchment.
Return the lasagna to the oven and cook for about 10 minutes, until deeply browned and bubbling.
Let the lasagna cool in the pan for 5 to 10 minutes before serving.