Prepare the vegetables by chopping and dicing them appropriately.
Heat a skillet over medium heat and sauté the onions and garlic until softened.
Transfer the sautéed mixture into the slow cooker along with the other prepared vegetables.
Pour in the vegetable broth and add the canned tomatoes, stirring gently.
Add the herbs—thyme, basil—as well as salt and pepper to taste, and stir well.
Set the slow cooker to low for 6-8 hours or high for 3-4 hours.
Once cooked, taste and adjust seasoning as necessary before serving.
Serve hot, garnished with fresh herbs if desired.