• Place a pot with plenty of salted water over medium to high heat. Once the water boils, add the rigatoni and boil for 7-8 minutes.
• Place a pot over high heat. Once hot, add a little olive oil, the sausages and sauté for 2-3 minutes, until golden brown.
• Add the onion, garlic, stir with a wooden spoon and sauté for 2 minutes.
• Add the canned tomatoes, rigatoni, thyme, stir and cook until the sauce thickens.
• Remove the pot from the heat, pour its contents into a rectangular casserole, measuring 33x25cm (13x10 inches), and set it aside.
• Preheat the oven at medium-high heat (190 °C/ 375° F), grill mode.

For the bechamel sauce:

• Place a pot over medium heat and add the butter. Once melted, add the flour and roast for about 2 minutes, stirring constantly with a hand whisk.
• Add the milk in batches, stirring constantly with the whisk. Season with salt and pepper and cook until the béchamel sauce thickens, stirring frequently.
• Pour the bechamel sauce over the rigatoni and bake for appx. 10 minutes until the bechamel sauce turns golden.
• Serve the rigatoni warm.