Cut the broccoli florets and stem into small chunks.
Heat the olive oil in a saucepan and gently cook the garlic for a minute or two until softened.
Add the broccoli and enough water to cover it. Stir in the stock cube.
Bring to the boil, then reduce the heat and simmer for 10–12 minutes, until the broccoli is tender.
Add most of the chickpeas and the watercress, reserving a few chickpeas and watercress leaves for serving.
Remove the pan from the heat and blend until smooth using a hand blender.
Stir in a squeeze of lemon juice and taste for seasoning.
Ladle into bowls and top with the reserved chickpeas and watercress leaves.
Serve warm with sourdough bread, gluten-free scones, or a simple salad on the side. For extra texture, you can also sprinkle over some toasted seeds or crispy chickpeas.