Heat olive oil in a large, heavy bottomed dutch oven or pot over medium-high heat. Add the beef and pork and season with salt and pepper. Break up the meat as it browns.
Continue cooking the meat until it’s about 80% browned, then add the garlic, onion and fennel. Season again with salt and pepper and continue cooking until the meat is fully browned and the onion and fennel are softened.
Add the fennel seed and crushed red pepper flakes, if using.
Add the white wine and let it cook down until it’s barely there, followed by the tomatoes, broth and milk. Bring to a strong simmer and then reduce the heat to medium-low. Let this sauce gently simmer for at least two hours, stirring occasionally.
Around the two hour mark, the sauce should be thickened considerably. If it still looks soupy, it needs more time.
Once the sauce is to your liking, add the butter and let it melt. Prepare your pasta.
When it’s time to mix the pasta with the sauce, lightly dress the pasta with bolognese.
