Over high heat, boil large pot of heavily salted water. Once boiling, add lasagna noodles and cook until al dente then drain and set aside.

To make bechamel sauce: In saucepan over medium-low heat, melt butter. Add flour and stir with wooden spoon until paste forms. Add small amount of milk and stir until mixture loosens. Gradually add remaining milk and continue stirring with whisk. Cook sauce over low heat until thickened, about 10 minutes.

Preheat oven to 375 F.

In large, deep, oven-proof casserole dish, ladle small amount of pasta sauce followed by small amount of bechamel sauce. Sprinkle some Parmigiano Reggiano cheese over sauces and layer with three lasagna noodles. Continue pattern until dish is complete. Top final layer of noodles with remaining bechamel sauce and grated Parmigiano Reggiano.

Bake 25-30 minutes until golden brown and bubbling. Cool prior to serving.