9x13 inch oven pan: 1， spaghetti sauce: ， lasagna: ， ricotta cheese: ， Parmesan cheese: ， beef ground: ， mozzarella cheese:
1Spread oil on the oven tray first, and then put 1 cup spaghetti sauce. Then put 4 layers lasagna and another 1 cup sauce on top.
2Heat the beef ground
3Spread ricotta cheese, mozzarella, and parmesan cheese.
4Put 1/2 cup sauce, and another 4 lasagna, then sauce again, and put beef on top.
5Put ricotta, mozzarella, parmesan, and sauce again.
64 layers of lasagna, sauce, mozzarella, and parmesan again. Then covered with tinfoil.
7Preheat oven to 375F, put in lasagna and bake for 1 hour.
看上去很复杂，其实一直在重复步骤，简单来讲就是 sauce noodles sauce cheese sauce noodle beef cheese sauce noodle cheese