Peel and dice the potatoes, and thinly slice the onions.

In a large pot, melt the butter over medium heat. Add the onions and garlic, and sauté until golden brown.

Add the diced potatoes and stock. Bring to a boil, then reduce heat and simmer until potatoes are tender.

Blend the soup until smooth, then stir in the heavy cream. Season with salt and pepper.

Serve hot, garnished with fresh chives or caramelized onions.