Trim asparagus; cut into 1-inch pieces (reserve tips for garnish).
Sauté leeks in butter/oil for 5–7 minutes until soft.
Stir in garlic and diced potato; cook for 2 minutes.
Add asparagus pieces and broth; season with salt and pepper.
Simmer for 15–20 minutes until vegetables are very tender.
Blend the soup until completely smooth using an immersion blender.
Stir in heavy cream and lemon juice; warm through on low heat.
Taste for seasoning and stir in lemon zest.
Garnish with blanched asparagus tips, chives, and olive oil.
Notes
Blanch asparagus tips separately in boiling water for 2 minutes for a perfect garnish.Clean leeks thoroughly to remove all grit.For an ultra-smooth texture, pass the puréed soup through a fine-mesh sieve.Add lemon juice only at the end to keep the flavor bright and fresh.Use a potato for natural thickness even if you omit the cream.Store in the fridge for up to 3 days; reheat gently.