Remove outer tough layer of leek; slice whites & pale green of leek into 1/4-inch rings, then place slices in a bowl of water. Gently swirl to loosen rings. Drain.

Melt butter over medium-low heat in a 2 quart sauce pan. Add fresh sage and sauté for 5-7 minutes or until sage leaves become slightly crispy. Remove sage and reserve for garnish.

Add leeks to butter and sauté until tender, about 10 minutes. Add bay leaf, garlic and thyme sprigs and cook an additional minute until garlic is fragrant.

Add diced potatoes and broth and simmer until potatoes are tender, about 30 minutes. Remove bay leaf and thyme sprigs, then stir in cream until heated through. Remove from heat and blend either using an immersion blender, or carefully in batches in a traditional blender until creamy and smooth. Season with salt & pepper to taste.

Serve warm, garnished with crispy sage leaves or served chilled.