Cook the lasagna noodles according to the package instructions. I cooked them for 10 minutes instead of 8, then drained and rinsed them with cold water. Spread them out in a baking dish, brush with 2 tablespoons olive oil, and let them cool.

Prepare a simple béchamel sauce with a pinch of salt.

Meanwhile, in a skillet with a little olive oil, sauté the finely chopped onion until translucent, then add the spinach. Once wilted, set aside to cool. After it cools, stir in 3/4 cup Parmesan and the ricotta cheese.

In a baking dish, spread a little béchamel sauce and place 4 lasagna noodles on top. Add a layer of the ricotta filling, a little Parmesan, and a little béchamel sauce.

Repeat the process for three layers. For the final layer, add the noodles, the ricotta mixture, béchamel sauce, and finish with Parmesan.