In a large skillet over medium high heat, brown the ground beef until cooked completely. Add the cooked ground beef to the bottom of the slow cooker pot.
In the same skillet over medium heat, add the onion and garlic and cook until the onion is translucent, pour in the red wine and bring to a simmer. Let simmer for 2-3 minutes to burn off the alcohol. Pour the red wine and onions into the slow cooker with the ground beef.
To the slow cooker, add the rest of the ingredients (not including the spaghetti) and stir. Cook on HIGH for 3-4 hours or LOW for 6-7 hours. During the last 20 minutes of cook time, cook the spaghetti according to package instructions on the stove top. Before serving, taste the sauce and adjust salt or seasoning if needed.
Serve the bolognese with the spaghetti by mixing some of the sauce into the spaghetti and then pouring more over the top.
Notes
This sauce freezes well! You can make a double batch and have some on hand all month.