Peel & dice the onion.
Heat the oil in a skillet and saute the onion until transparent.
Stir in the ground beef. Cook until browned.
Sprinkle the breadcrumbs over the top and mix to combine.
Mix in the cabbage, then the ricotta.
Melt butter in a saucepan over medium heat. Add flour and whisk until smooth.
First stir in the white wine, then the milk.
Season with salt and pepper.
Simmer until the sauce thickens.
Spread a thin layer of sauce on the bottom of a baking dish.
Stuff each with the filling.
Place next to each other in the baking dish with the open ends facing upwards.
Pour the remaining sauce around the outside and between the pasta.
Sprinkle evenly with cheese.
Bake for 30 minutes.