Prepare the ingredients: Wash the samphire thoroughly with plenty of water, and remove any tough stems. Set aside a few sprigs for serving. Peel and dice the potato.
Sauté the onion: Heat 3 tablespoons of extra virgin olive oil in a pot. Sauté the finely chopped onion over low heat for 5-6 minutes until softened. Add the crushed garlic and cook for another minute.
Cook the potato: Add the potato to the pot and sauté for 2-3 minutes. Add 6 cups of unsalted water and cook for 15 minutes until the potato is tender.
Add the samphire: Add the samphire and cook for 3-4 minutes. Do not overcook, as its color and aroma will be lost.
Blend: Add 2 tablespoons of lemon juice. Use an immersion blender to achieve a smooth consistency. Taste and add a little salt if necessary.
Serve: Pour into bowls. Drizzle the remaining olive oil over the top. Garnish with the fresh sprigs you set aside and serve hot.
