Heat 1 tbsp olive oil in a large skillet over medium high heat. Add garlic and onion, and cook until translucent and sweet - around 7 minutes. Transfer to slow cooker.
Heat 1 tbsp oil in the same skillet and increase heat to high. Add beef and cook, breaking it up as you go, until browned. Cook in 2 batches if your skillet is not large enough. Transfer to slow cooker.
Return skillet to the stove, turn the stove down to medium and add red wine. Bring to simmer and scrape all the brown bits off the bottom of the skillet into the wine, then pour the mixture into the slow cooker.
Add remaining ingredients into the slow cooker. Cook on Low for 6 hours.
Bring a large pot of water to boil and cook the spaghetti until just before al dente (still slightly firm). Remove 1 mug of the water from the pot, then drain the pasta.
Return the pasta to the pot and add 2 1/2 - 3 cups of Bolognese Sauce, plus 1/2 cup of reserved pasta water. Toss gently over medium high heat for 2 minutes, or until the Sauce has thickened and coats the spaghetti. (Note 3)
Serve immediately with freshly grated parmesan cheese if desired.
1. Bolognese Sauce freezes wonderfully! Allow to cool overnight then freeze in serving size portions.2. This recipe is a double batch and makes enough for 8 to 10 servings.3. This step of tossing the pasta with the sauce and some of the pasta water is called "emulsifying" and it's when the magic happens. The oil in the sauce and the starch in the pasta water come together to make the Bolognese Sauce thicker so it clings to every strand of the pasta. This is the proper Italian way of making pasta!*Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.