To prepare the béchamel sauce: melt the butter, add the flour, and pour in the milk, stirring to prevent lumps from forming. Add salt and a pinch of nutmeg. Bring to a boil and cook for a few minutes.
Grease a dish with the remaining butter, pour a layer of Barilla Ragù alla Bolognese and béchamel sauce over the bottom, then an alternating layer of uncooked Barilla Emiliane Lasagne all'Uovo, then finish with the ragù, béchamel, and Parmigiano Reggiano. Bake in the oven for 20 minutes at 220-220°C. Cool for 10 minutes before serving.