How to Cook Lasagne
To make lasagna, first cook lasagna noodles. Then, make a meat sauce by cooking onion and garlic with ground meat, adding seasonings, and simmering it with tomatoes and tomato sauce. Next, whip a beaten egg with ricotta cheese. When you're ready to build your lasagna, put a thin layer of sauce in a 9 by 13 by 2-inch baking dish. On top of that, make as many layers of noodles, cheese mixture, sauce, and mozzarella cheese as you have ingredients for, finishing with mozzarella cheese. Finally, cover your lasagna with foil and bake it for 30-40 minutes in a 375°F oven.
Cook the noodles in boiling water. Make sure you keep the entire lasagna noodle from breaking, as you will need unbroken sheets when you layer the dish later. Add a pinch of salt to the pot right before you add the noodles and let them cook according to the time on the box, usually 10-12 minutes. Stir occasionally, every 1-2 minutes. When they are done, drain the water and set aside the noodles to cool.  You will likely need you biggest pot, filled 2/3 with water, to fit the noodles. As you wait for the water to boil and noodles to cook you can move on to making the filling, however. Some companies sell "Oven Ready" noodles that don't need to be boiled, so be sure to read the box to check. Heat a tablespoon of oil in a large pan on medium heat. Do not move on until the oil is shimmering. This means it is hot, and adding ingredients too soon can lead to soggy, oily food. Add a diced medium white onion and 2 cloves of chopped garlic and cook for 2-3 minutes until they start becoming translucent. Translucent simply means that the edges of the onions have begun to turn clear. You do not need the onions to be fully cooked just yet. Looking to get more vegetables in your lasagna? Add 1/2 cup chopped carrots, celery and/or green peppers here as well for a heartier sauce. If you do, allow the vegetables to cook and extra 1-2 minutes. Add the 1lb of ground meat to the pan and cook until browned. Mix the meat in with the onions and garlic, stirring well, and cook on medium heat until completely browned. Add salt and crushed black pepper, to taste, as it cooks. If you have time, cook the meat in a separate pan, though this is not necessary. If you are using sausage, cut the casings off so you only have the ground meat inside. You can also take this time to add 1/2 tablespoon dried oregano, basil, or rosemary, or simply 1 tablespoon of dried Italian seasoning. Transfer the meat and vegetables to a large sauce pot on medium-low heat. The pot needs to be big enough to hold your sauce and tomatoes as well. This is a good time to check on your noodles if you've forgotten them. They should be pliable and soft, but still firm. Add the sauce and tomatoes to the saucepot and bring to a simmer. Pour your 28 ounces of sauce, 12 ounces of crushed tomatoes and 6 oz of tomato paste to the meat and vegetable mixture and stir well. Raise the heat to medium until the sauce comes to a low simmer, when occasional bubbles break the surface of the sauce. You can substitute 36 ounces of pre-made pasta sauce instead of the three different tomato products for a simpler sauce. Take this time to add any additional spices you want, such as garlic powder, sugar, or more seasoning, 1 teaspoon at a time. Many cooks like sugar to balance out the natural acidity of the tomatoes. Lower the heat if it is bubbling too much, you only want a low simmer. Cook the sauce on a low simmer for 10-15 minutes. The longer the sauce has to cook, the richer it will be. Stir it regularly, being sure to get down to the bottom so that nothing burns. When you're ready to build the lasagna, remove the sauce from heat and let it cool gently. The sauce does not have to be cold to move forward, but letting it cool slightly will make it easier to handle. Whip your ricotta together with the beaten egg. Whip up one egg with a fork, as if preparing scrambled eggs, and then mix it in with the ricotta. The egg will help the cheese bind with the layers of pasta, keeping your whole dish together when it is done cooking. Spoon a thin layer of sauce into the bottom of a large, oven-safe dish. You want something with tall sides, such as a 13x9x2" or 2-quart baking dish. Spread the sauce evenly, enough to cover the entire bottom of the dish. Lay lasagna noodles over the entire bottom of the dish. You should be able to get three noodles vertically layered over the bottom, slightly overlapping. While a little overlap (1" or less) is fine, feel free to trim the noodles with a clean pair of kitchen shears if need be. You want the entire bottom surface covered with noodle. Spoon 1/3 of the ricotta mixture evenly over the noodles. Spread a nice layer of the ricotta over the tops of the noodles so that every bite will be nice and cheesy. Be sure to save the other 2/3 -- you'll need it for the rest of the layers. Spoon 1/3 of the sauce over the ricotta. Get your filling into the pan, spooning it generously over the lasagna. Top the sauce with a generous coating of mozzarella. This final layer of cheese will complete your first layer of lasagna. Coat the top enough that the sauce is only poking out in a few places underneath, or use less for a slightly healthier option. Continue layering in this pattern --noodles, ricotta, sauce, mozzarella-- until you run out of noodles. The top and final layer should be mozzarella. Just keep layering your lasagna like this to end up with your final, glorious lasagna. Top with a sprinkling of freshly grated Parmesan or Romano cheese before putting in the oven. Bake for 30-40 minutes at 375℉, covered with aluminum foil. Put a layer of aluminum over the lasagna before it goes into the oven. To prevent the sauce from spilling over the edge as it heats up, you can also place the entire dish on a baking tray to keep the sauce from getting on your oven.  Since the dish is technically already cooked, putting it in the oven is meant to melt the cheese and let the flavors meld deliciously. That said, you can take it out when you feel like it is hot and ready to serve. Remove the foil for the last 5 minutes to brown and bubble the cheese on top. Let the lasagna sit for 10 minutes before serving. This lets the cheese re-solidify, just a bit, which will keep the layers from sliding off of one another when you serve the lasagna. Mix new flavors into your ricotta for a light taste addition. When mixing the egg into the ricotta, you can further customize the cheese to give subtle new flavors to the lasagna. Try adding: 1/2 cup Parmesan cheese, grated. 1 teaspoon salt and black pepper 1/2 cup minced parsley 1/2 tablespoon grated nutmeg. Cook "meaty" vegetables into your sauce for a vegetarian option. This can be a great substitute for meat, but vegetables can also become fantastic complements to a meat sauce as well. Cook the vegetables in the oil for 5-7 minutes, until tender, along with the onions and garlic, then proceed to make the sauce like usual. If you are using it along with meat, cut the following amounts in half and cook the vegetables separately, then add to the sauce with the meat. 1 large eggplant, diced. 1 large zucchini, sliced. 1 lb small white mushrooms, sliced. Create a layer of fried eggplant on top of the sauce. Cut your eggplant into 1/4-inch slices and fry until soft in 1-2 tablespoons of olive oil. Set aside and pat dry with a paper towel, then add the sliced eggplant after the sauce. Top with mozzarella and continue layering as normal, placing a layer of eggplant after every layer of sauce. You can also try layers of: Roasted butternut squash. Blanched spinach. Use polenta cakes instead of noodles for a gluten-free option. Just because you can't enjoy pasta doesn't mean you can't enjoy lasagna. Layer in thin polenta cakes instead, treating the rest of the recipe exactly as normal. Substitute spaghetti squash for noodles to make individual servings. This ingenious, low-carb recipe is not layered exactly the same way, but that doesn't make it any less delicious. To make it: Cut the squash in half and remove the seeds. Cook the squash in a baking dish, cut-side down, for 45-60 minutes (450℉) or until easily pierced with a fork. Pour roughly an inch of water into the pan to prevent them from drying out. Fill each squash half with layers, starting with 1-2 dollops of ricotta, then sauce and mozzarella. Repeat until full. Cook the mini lasagnas for 20 minutes in the oven (450℉), until the cheese is melted on top of the squash. Use some south of the border substitutions for Mexican lasagna. You can use grilled or shredded chicken instead of beef, if you'd like, though it is not necessary. The principles are all the same as Italian lasagna, but you can get a totally different dish with some simple swaps: Tomato Sauce → Taco Sauce Riccotta/Mozzarella → Queso Fresco/Cheddar Noodles → Corn Tortillas Italian seasoning → Ground Cumin, cayenne, red pepper, onion powder Add 1 can of black beans and 1 can of yellow corn to sauce mixture. 
Cook the noodles in boiling water. Heat a tablespoon of oil in a large pan on medium heat. Add a diced medium white onion and 2 cloves of chopped garlic and cook for 2-3 minutes until they start becoming translucent. Add the 1lb of ground meat to the pan and cook until browned. Transfer the meat and vegetables to a large sauce pot on medium-low heat. Add the sauce and tomatoes to the saucepot and bring to a simmer. Cook the sauce on a low simmer for 10-15 minutes. Whip your ricotta together with the beaten egg. Spoon a thin layer of sauce into the bottom of a large, oven-safe dish. Lay lasagna noodles over the entire bottom of the dish. Spoon 1/3 of the ricotta mixture evenly over the noodles. Spoon 1/3 of the sauce over the ricotta. Top the sauce with a generous coating of mozzarella. Continue layering in this pattern --noodles, ricotta, sauce, mozzarella-- until you run out of noodles. Bake for 30-40 minutes at 375℉, covered with aluminum foil. Let the lasagna sit for 10 minutes before serving. Mix new flavors into your ricotta for a light taste addition. Cook "meaty" vegetables into your sauce for a vegetarian option. Create a layer of fried eggplant on top of the sauce. Use polenta cakes instead of noodles for a gluten-free option. Substitute spaghetti squash for noodles to make individual servings. Use some south of the border substitutions for Mexican lasagna. 