For the béchamel:
100 gr (1/2 cup) flour, sifted
100 gr (1/2 cup) butter
1 lt (4 cups) whole milk, boiling
A pinch of ground nutmeg
For the lasagne:
1 kg (2 lbs) uncooked lasagne (store-bought or fresh)
200 gr (1 cup) pesto sauce
Extra virgin olive oil
½ stick of butter + more for greasing the oven pan
Step 1 Let's begin by whisking up the béchamel, which is the "hardest" part of this otherwise very simple recipe. While you preheat your oven at 180°C (356°F), melt the butter over low heat in a stainless steel pan. Gradually sprinkle in the flour, and stir well with a wooden spoon until smooth in consistency; cook gently until the mixture becomes a light golden color. Gradually add the boiling hot milk, stirring to avoid forming lumps. Cook for at least 15 minutes, stirring constantly.
Step 2 When the béchamel becomes rich and creamy in consistency-not too thick and not to runny, rather forming ribbons on the surface as it dribbles from the spoon-remove from the heat, adjust salt, and add a wee pinch of powdered nutmeg.
Step 3 Very good, upon completing this step, you're done 3/4 of the way. Is your appetite awakening? Now we blanch and build.
Step 4 Bring a large pot of lightly salted water to a rolling boil. Add a tablespoon of olive oil to it so the pasta won't stick during cooking. Cook the lasagne sheets for 5 minutes, fish them out with a slotted spoon and lay them flat to dry on a clean kitchen towel. Keep aside a glass of the pasta cooking water, and stir 2 tablespoons (or more) of it in the pesto sauce.
Step 5 Butter a large, high rimmed 9" x 13" baker pan, and lay a single layer of parboiled lasagna sheets to cover the bottom, just barely overlapping them. Smear evenly with 3-4 tablespoons of slightly diluted pesto sauce and a wee drizzle of olive oil. Next, slather on the béchamel and a few flakes of butter. Dust with a light hand of grated Parmigiano, and repeat the layers until you reach the top of the baker pan, or you run out of lasagna sheets. Should find you are running low on béchamel, you can always make more. It's never too much. On the other hand, having too little could signify a dry, parched final outcome. We want scrumptious, succulent and creamy.
Step 6 For best results, overdo the top layer with béchamel, butter flakes and grated Parmigiano.
Step 7 Bake your masterwork, warming it through in the oven for 10 minutes, or until a crispy, golden crust forms.
Step 8 The bitter sea tang of a good Vermentino white will offset the pesto's garlic perfectly, and have you smiling for days.