Melt butter in a large pot over medium heat.
Add onion, garlic, and leeks. Cook all for about 5 minutes until softened
Add in salt, pepper, potatoes and cayenne. Stir together and cover pot. Cook for an additional 5 minutes, or until potatoes begin to soften.
Add in vegetable broth and bring to a boil. Reduce heat to a low simmer.
Cook for an additional 10 minutes.
Using either an immersion blender or blender. Blend soup mixture until smooth and creamy and return to pot.
Return pureed soup to the pot, reduce heat to low and whisk in cream. Cook for an additional 3 minutes.
Top with chives, cheese or bacon and serve.