Heat olive oil in a pan slowly, add the shallots and allow to sweat until cooked and opaque. Remove shallots and drain, add the Yukon gold potatoes and increase heat, sear the potatoes in the hot oil until caramelized and golden, then add the shallots back to potatoes. Add boiling stock, reserving 1/2 cup, and the garlic to the potatoes, turn down heat to a simmer. Cook until potatoes are soft, add the cream, if desired, and blend. Pass mixture through a fine strainer. Season, to taste, with salt and pepper.
Boil the remainder of the stock, add the small garnishing potatoes and cook quickly. Then add the chopped truffle and butter. Reduce the stock until an emulsion coats the vegetables. Top the dish with chives.
To serve, top soup with garnish and sprinkle with chives.