Stuffed shells are a great meal to make ahead, and all you need to do is pop them in the oven and heat them up. Plus, a twelve ounce box of shells makes two trays of shells, so unless you are feeding a crowd, you can eat one now and put one in the freezer for later.
To make this really easy, I have the Bolognese sauce I made and froze back when my garden was in peak summer production. So first, I have to get one package (about a quart) out of the freezer and let it thaw for a day or two in the refrigerator.
Next, I make my own ricotta cheese. It’s very easy. I put a gallon of quality whole milk in a pot. Add 1t citric acid and 1 t sea salt. Heat over medium heat. Stir often, scraping the bottom of the pot to make sure it doesn’t stick. When the temperature gets over 160F or so, fine curds form. Keep stirring until the temperature gets to 190F and the whey clears. Cover the pot and let it sit for 10 minutes. Pour the contents of the pot into a colander lined with fine cheese cloth or muslin. If you like, you can collect the whey for another use. After about 20 minutes the cheese is drained. Scoop the cheese into a bowl and fold in ¼ cup heavy cream to make the cheese soft and rich. This makes about three pounds of cheese. Enough for one batch of shells. Put it in a container and refrigerate.
To make the filling for the shells, I start with a 10 ounce bag of spinach leaves. Clean the spinach, remove any large stems, and place in a microwave proof bowl. Cover with plastic. Microwave for 2-3 minutes. The plastic will suck down. Carefully lift an edge of the plastic and let the steam out. As soon as the spinach is cool enough to handle, scoop it into a sieve or onto a cotton muslin towel. If using a sieve, press out as much moisture as you can with a silicone spatula. If using a towel, roll the spinach into a ball and twist the towel to squeeze out as much moisture as you can. Chop the dried, cooked spinach.
Place the chopped spinach and ricotta in a large bowl. Add three eggs, ½ cup chopped fresh parsley, ½ t black pepper, 2-3 minced cloves of garlic, a cup of grated mozzarella and a cup of a sharper Italian cheese of your choosing (I used DOP Pecorino Toscano). Fold the mixture to blend all ingredients evenly. Add salt if desired, but I usually feel the cheeses provide enough salt.
Cook the shells. I typically use Barilla because that is what I can find most easily. If you want to make something special, try Conchiglioni Pasta di Gragnano. Artisan pasta from Italy is worth the added cost; after all, look at all the work that went into garden fresh Bolognese and homemade cheese.
Nine minutes is good. They will cook more in the oven, so do not overcook the pasta! When the pasta is al dente, drain in a colander and run under cool water to stop the cooking.
Put the Bolognese or whatever sauce you are using in a sauce pan and gently heat on the stove.
Prepare your baking pan with a little olive oil to prevent sticking. Add about 1-1/2 cups of the sauce to the bottom of the pan.
Fill each shell with 2-3T of the cheese mixture. As each shell is filled, place it on the base of sauce in the baking pan. Put the shells as close together as possible. When the pan is full, work on pan number two. When both pans are full, use the rest of the sauce to dress each shell with a small amount of sauce. If you like, you may add a little more cheese on top, like Pecorino Romano or Parmigiano Reggiano.
Cook in a 350F oven until the cheese is bubbly and the edges of the pasta just start to brown a bit.
Four shells per person is a nice serving as a main course, or three shells as a pasta course (depending on what else you are serving). I like to shake on some of my smoked red pepper flakes for a bit of extra spice.