Preheat your oven to 400F. Lightly drizzle the garlic heads with olive oil. Wrap each head in foil and roast for 45 minutes, or until the cloves are becoming caramelized and the garlic is very fragrant.

Heat the olive oil in a large pot over medium heat. Add the onion. Cook for 5-7 minutes, stirring often, or until the onion is tender and clear. Add the chickpeas, broth, 1 cup (240mL) water, salt, and pepper. Cover the pot and bring the mixture to a simmer.

Transfer the mixture in the pot to a powerful blender. Squeeze the roasted garlic cloves from both heads of garlic into the blender. Blend the ingredients on high till the mixture is very smooth. Take precaution with blending, as the hot soup will splatter. You can also use an immersion blender for this step.

Transfer the pureed soup back to the pot and bring to a simmer. Add the greens and cook for another 7-10 minutes, or until the greens are very tender. Stir in freshly squeezed lemon juice to taste (1-2 tablespoons) and add up to one extra cup water (240mL) if the soup is too thick for your liking. Adjust salt and pepper to taste. Serve.