1. Peel the onion and garlic and place them in the bowl with the ultrablade knife. Mix at speed 11 for 10 seconds. Replace the ultrablade knife with the mixer, add the oil and launch the P1 simmer program at 270°F for 5 minutes.
2. Add the meat, drained tomatoes, tomato sauce and oregano. Season with salt and pepper. Launch the P2 simmer program at 190°F for 35 minutes. Remove the sauce and wash the Prep&Cook bowl.
3. Preheat the oven to 350°F.
4. Place the flour, milk and nutmeg in the bowl fitted with the whisk. Season with salt and pepper. Mix at speed 7 for 1 minute. Add butter and launch the sauce program at speed 4 at 190°F for 8 minutes.
5. Oil a 13 x 9-inch oven dish and pour in a little of the tomato sauce. Cover with lasagna sheets, add a little tomato sauce, white sauce and shredded cheese. Repeat this step, until all the ingredients are used, finishing with cheese. Cover with foil and bake for 25-30 minutes.