Peel the onion and garlic and place them in the bowl with the ultrablade knife, then mix at speed 11 for 10 s. Replace the ultrablade knife with the mixer, add the oil and launch the P1 slow cook program at 130°C for 5 mins.
Add the meat, tomatoes and oregano. Season with salt and pepper and launch the P2 slow cook program at 90°C for 35 mins. Set the sauce aside and clean the bowl.
Preheat the oven to 180°C. Place the flour, milk and nutmeg in the bowl fitted with the whisk. Season with salt and pepper. Mix at speed 7 for 1 min. Add the butter and launch the sauce program at 90°C at speed 4 for 8 mins.
Oil an oven dish and pour in a little of the tomato sauce. Cover with lasagna sheets, add some tomato sauce, white sauce and grated tasty cheese. Repeat this step until all the ingredients are used, finishing off with grated tasty cheese. Cook in the oven for 25 to 30 mins.