To make the sauce:
Cook the bacon lightly to render out the fat and drain on paper towels. Chop cooked bacon into small pieces.
While the bacon is cooking, place the dried porcini in a small bowl and cover with hot water to soak.
If you want to use the rendered bacon fat, heat 1–2 tablespoons in a large pot (or use olive oil instead). Add and sauté the chopped onion and celery until soft. Add the minced garlic and continue to sauté until vegetables just start to brown.
Drain and chop the porcini and add to the pot. If you want to use the porcini soaking liquid in the sauce, strain out any grit and add the liquid to the pot along with the star anise, cloves, and wine. Stir to deglaze. Add the beef stock, crushed tomatoes, dried herbs, sherry vinegar, Worchester, and cooked bacon to the pot. Let the sauce simmer on low while you make the meatballs. Before serving, stir in the heavy cream and grated Parmigiano Reggiano.
To make the meatballs:
If using frozen spinach, thaw and drain, then squeeze out excess liquid and chop if necessary. If using fresh spinach, wash, drain (leaving some water clinging to the leaves), and drop into a hot skillet. Stir as needed until all leaves are completely wilted. Cool the wilted spinach and squeeze out excess liquid. Chop and add to a large bowl.
Place all remaining ingredients (except breadcrumbs) in the bowl with the chopped spinach and mix with your hands. Add in 2 cups breadcrumbs and knead into the meat mixture. Form the mixture into balls of any size you like.
Place remaining breadcrumbs in a shallow bowl and roll each meatball in the reserved breadcrumbs to coat.
Heat 2 tablespoons olive oil (or bacon fat) in a large skillet. Add as many meatballs as will fit in the skillet and cook, turning frequently, until they are browned on all sides and cooked through, about 15 minutes. You may need to cook the meatballs in two batches, depending on the size of your skillet. Keep meatballs warm until ready to serve.
To make the pasta:
Mound up the flour on a clean work surface and make a well in the middle. Add the eggs, olive oil, and salt to the center and break up the eggs gently with a fork as you coax flour gradually into the egg mixture. As the dough starts to come together, continue working it with your hands until you have a shaggy ball of dough.
Knead for 8 to 10 minutes until the dough starts to feel smooth. If it seems too dry, dip your fingertips into a bowl of water to add in some moisture. If it’s too sticky, sprinkle a little more flour over the dough and onto your work surface. Shape the dough into a ball, cover with a towel, and let rest at room temperature for 30 minutes.
Set up a couple large baking sheets and dust with flour so you have more work surfaces that can hold the dough as you roll it out.
Cut the dough into 4 pieces and flatten each into an oval disk. You can make pasta entirely with a rolling pin and a knife, but if you have a pasta roller, run each disk through your pasta roller set on its widest setting. Fold both short ends of the elongated disks toward the center, then fold in half to form a rectangle and run the pieces through the pasta roller reset on level 2 and again on levels 4, 5, and 6. Each time you roll the dough pieces, you may need to sprinkle them with flour to keep things from sticking.
The final step is to cut the pasta, which you can do if you have a pasta cutter attachment to your roller but cutting by hand with a knife works nicely if you like a more rustic end product. Cook the pasta in a pot of salted boiling water for 2–4 minutes.