For the sausage ragu, squeeze the sausage meat from the casings and roughly chop. Place a frypan over medium heat and add the chopped sausage and onion. As soon as it becomes fragrant,reduce the heat to low and cook until caramelised (about 10 minutes). Add the garlic,carrot and celery and cook for an additional 10 minutes. Add the wine and tomatoes and cover. Simmer for two hours or until the sausage has started to break down and soften and the liquid has reduced (aim for a bolognese-like consistency).
For the bechamel, combine milk,onion,garlic,cloves and bay leaf in a saucepan and bring to the boil over medium heat. Reduce heat to low and simmer for five minutes. Remove bay leaf and keep warm.
In a separate heavy-based saucepan,melt the butter,then add flour and stir over medium heat until combined and starting to colour (one to two minutes). Remove from heat and gradually whisk in the milk mixture until well combined and smooth. Return pan to low heat and cook,stirring,until sauce thickly coats the back of a wooden spoon (10 to 15 minutes). Season to taste with nutmeg,sea salt and freshly ground black pepper. Keep warm.
Preheat oven to 175C.
To assemble the lasagne, place three lasagne sheets in the base of the dish. Spread one-quarter of the ragu sauce on top followed by enough bechamel to just cover,and scatter over a few pieces of mozzarella. Repeat with remaining sauce,bechamel,cheese and pasta sheets. Pour any remaining bechamel sauce evenly over the final layer of mozzarella,then sprinkle with parmesan.
Bake for 30 minutes,or until the cheese has browned and the sauce is bubbling. Remove the lasagne from the oven and let it stand at room temperature for 10 minutes before serving.
More lasagne recipes
Find more of Katrina Meynink's recipes in theGood Food Favourite Recipes cookbook.