In a large skillet cook the chopped bacon over medium-high heat until browned and crispy. Remove from the pan and drain on a plate lined with paper towels. Drain off any excess grease.
Add the sirloin to the pan and cook while breaking up into chunks with a spatula until browned. Add the garlic and bay leaves. Season with salt and pepper to taste. Cook stirring frequently for about 10 minutes. Add the wine and deglaze the pan, scraping up any brown bits from the bottom. Add the beef stock and tomato paste.
Stir in the crushed tomatoes and bacon. Simmer until the sauce has thickened.
Bring a large pot of lightly salted water to a boil. Cook thin spaghetti according to package directions. Drain the water from the noodles.
Serve the sauce over the cooked noodles. Top with chopped Italian parsley and grated parmesan cheese.