We deglaze the pan with a quarter cup of sauce, scraping up the browned bits. We add this sauce and the sausage to the pot of sauce and simmer gently while we cook the sirloin.
To the pan, we add the remaining oil and the garlic cloves and heat until the garlic is aromatic. We then add the sirloin, some salt and pepper, and brown it until no pink remains. We drain the meat on a paper towel-lined plate and discard the garlic cloves. We add the cooked meat to the simmering sauce and cook gently for about 10 minutes to meld the flavors.
We divide the meat sauce between two quart containers, putting all of the meat and a little sauce in the containers. The rest of the plain sauce is put in a bowl to be used for the bottom and top of the lasagne. We cool the containers, and then cover and refrigerate.
The next morning, we continue our preparation. Nanny has often suggested straining the ricotta cheese to get rid of the excess liquid which sometimes makes the lasagne “watery”. She has not tried it herself – instead she adds a tablespoon of flour to the ricotta when mixing the cheese – but we decide to try it. We put the contents of the large container of ricotta in a fine strainer and set it over a bowl. We cover it with plastic wrap and refrigerate it for 8 hours.
In the evening, we are ready to assemble the lasagne. We start by heating a large pot of water for our dried lasagne noodles.
When the water is boiling for the pasta, we add the noodles from the package. We stir and cook for about 10 minutes. The noodles are drained when they are just al dente. Having drained the noodles, we spread them in a single layer on wax paper with a pair of tongs. We let them cool while we prepare the cheeses.
Over a piece of wax paper, we grate the mozzarella using our box grater. We put the shredded mozzarella into a large bowl, reserving ¼ cup for the top of the lasagne in a small baggie. The parsley leaves are quickly chopped and added to the shredded mozzarella with the Locatelli and drained ricotta cheese. We add some salt and freshly ground black pepper, stir, and taste for seasoning (it’s delicious!). At this time, the beaten egg is added and combined.
All the ingredients are cold as we assemble the lasagne since we are not baking it tonight. We coat the bottom of a 13 × 9 inch baking pan with some of the plain tomato sauce. Arranging 4 pieces of lasagne lengthwise, overlapping the edges slightly, we begin the layering. The noodles are topped with a third of the ricotta filling, spread with a spatula as best we can, and a little more than ½ quart of the meat mixture spread on.
We add 5 more lasagne, perpendicular to the first batch. We cut off the excess noodle with scissors (that’s how Nanny always did it). The trimmings are set aside.
The next layer is topped with another third of ricotta, and more meat, followed by another 4 pieces of lasagne lengthwise. The remaining fillings are spread on leaving a ½ cup or so of the meat mixture and the rest of the plain tomato sauce that was not used to line the pan.
We lay the final layer of noodles crosswise. We spoon some of the plain sauce to lightly cover. We cover with plastic wrap and then foil and refrigerate until tomorrow night. The rest of the meat, the lasagne trimmings, the plain sauce, and the reserved mozzarella are also refrigerated.
Tonight, we bake the lasagne and heat the trimmings of lasagne for the children. We begin by pre-heating the oven to 375 degrees. We remove the plastic wrap and sprinkle on more of the plain sauce and the reserved mozzarella. We place the pan, covered with just the foil, into the pre-heated oven and bake for 50 minutes. When it is bubbling, we remove the foil and bake the lasagne for another 10 minutes.
We combine the rest of the refrigerated plain sauce and meat and heat in the microwave to be served as additional meat sauce.
When we check the lasagne in the center, it is not hot enough, so we put the pan back in for another 5-10 minutes until it is nice and hot.
We remove the bubbling pan from the oven, cover loosely with the foil, and allow it to rest for 10 minutes. The lasagne is served with the additional hot tomato sauce and red pepper flakes.