The combination of spinach and cheese is common in Italian cooking. It is often referred to as “Di Magro,” referring to the fact that is contains no meat. While the literal translation is skinny or lean, these dishes are as filling and rich as any meat dishes!
Like a few other dishes I make, this one originates with something I ate, enjoyed, and then perfected to my taste. In the mid-1980’s I worked in Bethesda, Maryland. Bethesda, even then, was full of great places to eat. One of my favorite places to grab lunch was a place on Wisconsin Avenue. The restaurant had a bold sign across its façade which read “STROMBOLI.” The restaurant is still there, but I have not been there in many years. Two of my favorite Stromboli were made with cheese and either spinach or broccoli.
Of course I started making this at home because it was really, really good. I worked on making it to my taste. It’s bread, cheese, and other stuff, so how hard can it be?
The bread is very similar to my pizza dough, but made with a bit more hydration. I start the night before by making my typical sourdough sponge. One cup of active sourdough starter, 1-1/2 cups of Italian tipo 00 flour, and 1-1/2 cups cool dechlorinated water. Mix well, and let it sit on the kitchen counter overnight. In the morning, add 1T coarse Korean sea salt and half the remaining flour. I don’t weigh the flour since I have a rough idea of the volumetric weight equivalent and the look of different hydration levels in my dough. You want to shoot for about 65% hydration of this dough, meaning the weight of the water is 65% of the total weight of flour. Between the starter and the sponge, this contains about 20 ounces of water. 20 ounces is 65% of just under two pounds of flour, call it 30 ounces since you may work in some bench flour while working the dough.
I use a stand mixer to perform most of the kneading. Knead until the dough is smooth and elastic, then continue to add the remaining flour in small increments, allowing it to work into the dough. 65% hydration dough will still be pretty sticky, so I work the last flour addition lightly to allow the ball of dough to retain a light coating of flour, allowing it to be handled more easily. Let the dough rise several hours until it is doubled in size.
Put some bench flour out and scoop the risen dough onto the floured surface. Cut the dough in half to make two large Stromboli. Work each piece of dough and roll back into a ball. Cover loosely with a moistened towel while you prepare the filling.
You may make the cheese ahead of time. You will need one gallon of good whole milk for the ricotta, and another gallon for the mozzarella.
For the ricotta, heat the milk over medium heat. Once it gets to about room temperature, stir in 1t citric acid and 1 t salt. Stir and heat until curds form. Continue heating until the whey is clear, not milky in appearance. Remove the pot from the hot stove, and let it rest for 20 minutes. Strain the cheese through a cheesecloth lined colander. I let it drain pretty well, maybe an hour. Scoop the cheese into a bowl and work in a little heavy cream to smooth the texture. Taste, and add more salt if needed. As a variation, you can spread this cheese out in a sheet pan and cold smoke it a little bit. A gallon of milk makes about five cups of ricotta.
For the mozzarella, heat a gallon of high quality whole milk to room temperature. If you use milk that was Pasteurized at high temperature, this cheese will not have the right texture. Add 1t citric acid to the milk and slowly heat to about 90F while stirring. While it is heating, add 1/4t liquid rennet and 1/4t lipase to ¼ cup cool, dechlorinated water. Add this to the milk when it reaches 90F or you see it start to curdle. Continue heating a lightly stirring until the why is clear and the curds a large soft clouds (~180F). Remove the pot from the heat and let it sit undisturbed for 10 minutes. Scoop the curds out of the pot with a strainer. Heat the whey until it is at least 170F; it can go hotter, but this is about the limit my hands will take. Put the curds in a large bowl. Knead the curds a bit to squeeze out the whey and to form a rough ball. Lower the ball of cheese into the hot whey. When it appears to soften, lift it out, and while wearing rubber gloves, knead and stretch the cheese. If it tears, it needs more heat. Repeat the process until the cheese looks smooth and shiny. Since we’re not presenting this cheese to eat fresh as is, it does not have to have perfect appearance.
Now for the rest of the filling. Wash about 8 ounces of fresh spinach. Blanch the spinach briefly until it wilts. Shock with cool water, and then squeeze it until you cannot get any more juice out of it. Roughly chop. Roughly chop ¼ cup of flat leaf parsley and 6 cloves garlic.
Dice the fresh mozzarella and put in a large bowl. Add the chilled ricotta, spinach, parsley, and garlic. I like to add some smoked red pepper flakes (a little smoke even on store bought red pepper flakes makes a huge improvement!). Salt and pepper to taste. I mix in two eggs to help the cheese bind; today I used duck eggs for added eggy richness.
Oil a half sheet pan with olive oil. Preheat oven to 400-450F. I use the convection bake setting for this.
Spread out some bench flour, and stretch each of the dough balls into a rectangle. Properly relaxed dough should stretch without springing back. If your dough constricts, just keep stretching it until it complies. Do not roll the dough with a rolling pin; this will make it tough. Try to work the dough gently.
Put half of the cheese filling over the middle of the rectangle of dough. Try not to just roll up the loaf or you will end up with raw dough inside the Stromboli. The crust will cook too fast before the dough in the middle cooks. Fold the edges over to form into a loaf. Seal any holes and seams. Poke a hole in the top of the loaf to allow steam to escape. Place the loaf on the oiled sheet pan, and reshape as needed to make it uniform. Repeat the process with the second ball of dough and the rest of the filling.
Leave space between the loaves. Sometimes the cheese finds a way out during baking, and sometimes the loaves expand and converge. That’s all ok, but try to avoid it if you can.
Bake until the loaves are well browned. Remove the pan from the oven and let it rest for 20 minutes before cutting. Transfer to cutting board and cut several large slabs for each person.
You may serve this with marinara sauce, but I prefer to top with fermented hot sauce. Enjoy!