Delish Easy Casserole

1 pound pasta (maccaroni, or penne are best for this)
1 package frozen chopped spinach, defrosted and drained
1 pound ground meat (I used beef, but pork, lamb, or turkey would all be good in this)
1 large yellow onion, chopped.
1/4 cup flour
3 cups milk
2 tbsp butter
2 cups parmesean cheese (fresh, not the canned kind)

Boil your pasta and set aside to drain.
Brown your meat in a frying pan and add your onion. Cook until onion is soft, and then add your spinach. Saute until warm, set aside.
In a medium saucepan, melt your butter and stir in your flour. You are making a roux; cook using a wisk until the mixture boils but you dont want it to brown too much. Wisk in your 3 cups of milk, and cook over medium heat until sauce begins to thicken. Add 1 cup parmesean cheese and stir until melted.
Meanwhile, Toss the meat, onion, and spinach mixture into the noodles and then pour your cheese mixture over the top and toss well. Pour into a well greased pyrex baking dish or casserole dish. Top with remaining parmesean cheese and bake for 15-20 min at 375 degrees. To crisp up the top, set under broiler for a few minutes.