<human>:  How do I make a pan of lasagna at home?
<bot>: To make a homemade lasagna, start by preheating your oven to 375°F. Boil 12-14 lasagna noodles in salted water until they are al dente. Next, prepare the filling by combining 15 ounces of ricotta cheese, 1 beaten egg, and 1 teaspoon of dried parsley. In a separate bowl, mix together 1 pound of cooked and crumbled ground beef, 1 ½ cups of grated parmesan cheese, 2 cups of prepared marinara sauce, and 1 cup of chopped onion. Assemble the lasagna by spreading one cup of marinara sauce in the bottom of a 9x13 baking pan. Place 4 boiled lasagna noodles on top. Layer with one-third of the ricotta cheese mixture, one-half of the beef mixture, and 1 cup of shredded mozzarella cheese. Repeat the layers two more times. Lastly, top the lasagna with the remaining marinara sauce and the remaining parmesan cheese. Bake the lasagna for 45-60 minutes, until it is lightly browned and bubbling.