Begin by thinly slicing three large yellow onions. Heat 2 tablespoons of olive oil in a large skillet over medium heat, then add the onions. Cook them gently for 30-40 minutes, stirring occasionally, until they are golden brown and caramelized.

In the same skillet, lower the heat slightly and add 2 tablespoons of butter. Once melted, whisk in 2 tablespoons of flour, cooking for about 1 minute to form a roux. Gradually pour in 1 cup of heavy cream while whisking continuously, allowing it to thicken for about 5 minutes.

Bring a large pot of salted water to a boil and add 8 oz of cavatappi macaroni. Cook the pasta until just shy of al dente, about 6-7 minutes. Drain the pasta and gently stir it into the warm béchamel sauce.

Carefully mix the remaining caramelized onions into the pasta and béchamel mixture. Transfer everything into an oven-safe baking dish, spreading it out evenly.

Preheat your oven to 350°F (175°C). Prepare breadcrumbs by toasting pieces of baguette in olive oil until golden and crispy. Layer these breadcrumbs evenly over the pasta mixture.

Bake in the preheated oven for 10-15 minutes or until the top is golden brown and irresistible.

Once baked to perfection, remove from the oven and let it cool slightly. Serve it hot, garnished with fresh parsley.