Finely mince parsley. Beat the egg in a medium sized bowl and add the container of ricotta cheese. Mix the egg, ricotta cheese, parsley and salt and pepper. Cover with plastic wrap and put in the refrigerator until your ready to assemble your lasagna.
Get the largest pot you have and fill ¾ with water and place on a burner on medium low heat. This will be the pot you'll boil your lasagna noodles in. Don't try to squeeze the long noodles in a pot that is too small. The noodles will stick together and tear while they are cooking.
Cook the sausage in a skillet per package directions. Drain on a paper towel and slice into medallions.
Brown the ground beef in a large pot with the chopped garlic and drain. Put the ground beef back in the pot you browned it in and add the jar of sauce. Simmer on low, stirring occasionally.
While the sauce is warming and the water for the noodles is heating dice up the ball of mozzarella cheese. Turn the heat up to high on the pot of water. Bring the water to a boil. Add ¾ of one box of the lasagna noodles. You want the noodles to be able to move around in the boiling water without sticking and tearing. It's a bit more work to cook the pasta in batches but I have found that it cuts way down on the number of noodles that tear and stick together.
Allow the pasta and water to come back up to a boil and cook for 12 minutes, stirring occasionally to make sure the noodles aren't sticking to each other or the bottom of the pot.
Assemble your ingredients on the counter. Place a colander over a bowl next to the pot of boiling pasta. Turn the heat off on the sauce.
Once the 12 minutes is up carefully remove each piece of pasta from the pot with tongs and put it into the colander. Once you have all the pasta in the colander run cold water over the pasta being sure to move the pasta around so each piece comes in contact with the cold water. This helps to keep the pasta from sticking together while you are assembling your trays.
Add more water to the pot you cooked the noodles in and bring back to a boil. Add the rest of the first box of lasagna noodles and half of the other box. Cook the pasta the same way you cooked the first batch.
Now begin assembling your first layer of lasagna by ladling some sauce onto the bottom of both the large and small baking pans until it is covered. Begin layering the lasagna noodles, slightly overlapping them in the bottom of each baking pan.Next ladle a layer of sauce on top of the noodles. Now randomly drop tablespoons full of ricotta over the sauce. Next sprinkle some of the shredded mozzarella cheese over the sauce and ricotta cheese. Now add a layer of sausage. Now sprinkle with some of the diced mozzarella cheese. This completes your first layer.
Repeat step 8,9 and 10 with the remaining ingredients. You should get 3 layers in each of your pans out of the amount of ingredients I used. Keep a watch on the amount of cheese you are using for each layer. You want to make sure you have enough cheese for the top and final layer.
Loosely cover the tray with aluminum foil. Bake in a preheated 375 F. degree oven for 60 minutes or until the cheese has melted and the sauce is bubbling.