Boil salted water and cook lasagna noodles for 1 minute longer than al dente. Drain and rinse with cold water.
STEP 3
Melt butter in a saucepan over medium heat, add flour, and whisk in milk with a pinch of salt and pepper, cooking until thickened (6-8 minutes). Cool slightly.
STEP 4
Beat egg in a bowl, then stir in ricotta, spinach, 1.5 cups mozzarella, 0.5 cup Parmesan, 0.5 cup pesto, salt, and pepper. Mix remaining pesto into the bechamel sauce.
STEP 5
Brush an oil-coated baking dish with 0.25 cup pesto-bechamel sauce at the bottom.
STEP 6
Spread 1/3 cup of the ricotta mixture on each noodle, roll tightly and place seam-side down in the dish. Repeat for all noodles.
STEP 7
Spoon remaining pesto-bechamel sauce on top, then sprinkle with remaining mozzarella and Parmesan. Cover with foil and bake for 20 minutes, uncovered bake for another 10 minutes until cheese is bubbly and golden.
STEP 8
Let stand for 5 minutes before serving, optional to sprinkle with crushed red pepper.