Serves 4 Preheat your oven to 450°F.
Line a baking sheet with foil or parchment paper. Wash and dry the tomatoes, and remove the stems.
Slice the tomatoes in half, then in half again, making 4 wedges.
Place the tomatoes on the baking sheet, drizzle them with olive oil, and sprinkle them with sea salt.
Roast the tomatoes in the oven for 20 minutes.
Transfer the cooked tomatoes to a slow cooker.
Add the carrots, celery, onion, garlic, mushrooms, broth, basil, parsley, bay leaf, sea salt, and pepper to the slow cooker.
Cook on low for 4-6 hours. During the last 45 minutes of cooking, add the zucchini and spinach or kale.
When the soup is done, remove and discard the bay leaf.
Stir the soup to break up the tomatoes, or, if needed, use kitchen scissors to cut the tomatoes into smaller chunks.
Enjoy a big bowl of soup or serve alongside your favorite protein.