Preheat the oven to 180°C (350°F) for roasting the vegetables.

Trim the tops of the fennel bulbs and slice them into wedges. Chop the onion into small pieces.

Toss fennel wedges, onion, and whole garlic cloves with oil. Season with salt and pepper. Spread on a baking sheet and roast for 25–30 minutes.

Remove the vegetables from the oven, squeeze the garlic from its skins into a stockpot, and add the roasted fennel and onion with vegetable stock. Simmer for 5 minutes.

Blend the mixture until silky smooth. Stir in coconut milk, lemon juice, spinach, and parsley. Blend briefly to incorporate.

Taste and adjust seasoning with salt, pepper, or lemon juice before serving.