In a large saucepan melt
butter over medium-high heat until bubbling. Add onions
and saute until translucent. Sprinkle with flour, stirring constantly and cook until the mixture begins to thicken. Gradually whisk in the wine
, if using, and then gradually whisk
in the milk
and cook until smooth, thick and creamy. Combine the meat sauce and pasta
, and then pour in half the pasta mixture. Spoon half the bechamel over the pasta and top with half the cheese
. Repeat with the remaining ingredients. Bake 30 to 45 minutes until browned and bubbly.