Preheat oven to 450°F (232°C). Line a baking sheet with parchment paper.

Wrap garlic cloves in foil and arrange on the baking sheet with tomatoes and onion quarters. Drizzle with olive oil, salt, and pepper. Roast for 20-25 minutes, or until tomatoes and onions are caramelized.

Peel the garlic and transfer roasted vegetables to a blender.

Add diced tomatoes, chickpeas, balsamic vinegar, maple syrup, thyme, red pepper flakes, and salt to the blender. Blend until smooth and creamy. If the soup is too thick, add a little water or vegetable broth.

Lower oven temperature to 400°F (204°C). Line a baking sheet with parchment paper.

Sprinkle vegan mozzarella on 4 slices of bread. Top with remaining 4 slices. Drizzle outside of bread with olive oil. Bake for 8 minutes, or until golden brown and cheese is melted.

Let croutons cool slightly before slicing into cubes.

Serve soup topped with croutons, extra thyme, red pepper flakes, and chickpeas.