In a large saucepan over medium-low heat, melt the butter. Add the leeks, shallot and garlic and cook for 5-10 minutes, or until the leeks are tender.
Add the vegetable stock and bring to a boil. Add fresh peas and cook for 5 minutes, until tender. Stir in cilantro. Remove from heat and transfer to a blender; pulse until very smooth (You may need to work in batches). Season with salt and pepper. Divide between two bowls, drizzle with cream, if desired, and garnish with more cilantro.