Preheat the oven to 450° F and line a baking sheet with parchment paper.
Wrap the garlic cloves in a piece of foil and place it on the baking sheet along with the whole tomatoes and the onion wedges. Drizzle with olive oil and a pinch of salt and pepper and roast for 20 to 25 minutes, or until the tomatoes and onions are well browned. Peel the garlic and transfer the roasted vegetables to a blender.
Reduce the oven heat to 400° F and line the baking sheet with a fresh sheet of parchment paper.
To the blender, add the canned tomatoes, garbanzo beans, thyme leaves, 1 tablespoon olive oil, red pepper flakes, ½ teaspoon sea salt, and freshly ground pepper and blend until creamy. Taste and adjust seasonings as desired.
If the soup is not hot, put into a pot to re-heat.
