Lasagna with ham, spinach, and ricotta cheese

Preheat the oven to 400°F (205°C).

In a large pot of boiling salted water, cook the pasta until al dente. Drain.

In the same pot, melt the butter over medium heat. Sprinkle in the flour and cook for 1 minute, stirring constantly.

Gradually pour the milk into the saucepan while whisking, and whisk until the sauce is smooth. Add the mustard and nutmeg, then season with salt and pepper. Bring to a boil while whisking, then simmer for 2 to 3 minutes, stirring, until thickened. Remove from heat and keep warm.

In a bowl, combine the ricotta and Parmesan cheese. Season with salt and pepper.

In a large pan, heat the oil over medium heat. Cook the spinach for 1 to 2 minutes, until wilted. Remove from the heat and let cool.

Squeeze the spinach firmly over the sink with your hands to remove as much water as possible. Stir the spinach into the ricotta mixture.

Pour a little sauce into the bottom of a 13 x 9-inch baking dish. Cover with three lasagna noodles.

Spread half of the ham and half of the ricotta mixture over the noodles. Cover with a little sauce. Add three lasagna noodles, then repeat with the remaining ham and ricotta mixture and a little sauce.

Cover with the remaining lasagna noodles, then top with the remaining sauce. Garnish with mozzarella.

Bake for 30 to 40 minutes, until the mozzarella is golden brown and bubbling. Remove from the oven and let rest for 5 minutes before serving.