Heat butter in a saucepan over medium heat. Add the leek and toss to coat. Reduce heat to medium-low and cook covered, stirring occasionally, for 10 minutes.

Add the potato, stock and water to the pan. Cover and bring to a simmer over medium-high heat. Reduce heat to medium and cook, partially covered, for 20 minutes or until potato is tender. Set aside for 10 minutes to cool.

Using a stick blender, blend until soup is completely smooth.

Place the soup back on the stove over medium-low heat. Add the cream and cook, stirring, for 5 minutes or until heated through.

In a small frying pan on high heat add diced bacon. Cook until bacon starts to colour. Cook for longer if you want your diced bacon to be crunchy.

Season the soup with salt and pepper to taste. Sprinkle with bacon on top before serving. Accompany soup with warm crusty bread or bread rolls.