Arrange tomatoes, bell peppers, zucchini, summer squash, eggplant, garlic, and onions on a baking sheet, cut side down, in a single layer. Drizzle generously with olive oil and salt. Bake for 35-40 minutes, until eggplant, and bell peppers, have a slight char on their skins. Check at 25 minutes, as garlic (cloves or scapes) may need to come out earlier so they don’t burn.
Working in batches, pulse vegetables in a food processor until they break down but there are still large chunks (do not puree). Transfer vegetables to a large pot and add vegetable broth and thyme. Cook for 15 minutes over medium heat, stirring occasionally.
If you’d like to add a little creaminess to the soup, you can add coconut milk, but I think the soup is delicious without it as well. If you do add coconut milk, cook for 2-3 minutes more. Adjust salt and pepper to taste.