In a large stockpot or dutch oven, heat the olive oil over medium heat. Add the sliced leeks and chopped potatoes and cook until the vegetables have begun to soften and brown slightly, about 5-10 minutes.
Add the chicken or vegetable stock and bring to a boil. Reduce the heat to low and simmer for about 30 -35 minutes or until the vegetables are tender and soft.
Blend until somewhat smooth using an immersion or hand blender; I like a little chunkiness in my soup so I didn’t blend it all completely. I left a few potatoes chunks. Add the heavy cream and season with salt, pepper and the lemon juice.
Serve and garnish with the crème fraiche and fresh chives. Mix and enjoy!