Prepare your tomatoes by washing in plain water. Cut them in half or quarters and add to the crockpot. Add the garlic, onion, carrot, and herbs. Drizzle the wine and olive oil. Cover and turn crockpot to low and cook for 2-4 hours stirring occasionally.
After the sauce has simmered for a while and tomatoes have released their juices and the vegetables are soft, turn off crockpot and allow the sauce to cool.
Run the cooled tomato sauce through a Food Strainer or Food Mill to remove skins, seeds, and to smooth out the sauce. If you are crunched for time, you can pop the cooled sauce into the refrigerator and begin again the following day.
Return the strained tomato sauce to the crockpot to cook down further to thicken the sauce. Turn the crockpot to low and vent the cover so excess moisture evaporates. Cook until your desired thickness, 4-6 hours or longer, stirring occasionally.
Once the tomato sauce is nice and thick, taste it. Add salt and pepper and stir to mix in. Taste again. Adjust seasoning if needed. If the flavor is sharp and acidic, add a little honey and taste again.
If you are including additional ingredients such as mushrooms, green peppers, sausage, or meatballs, precook these and add to the crockpot and cook on low for an additional 1-2 hours.