Potato, Leek, and Truffle Soup Shooters

Ingredients

• 1 1/2 lbs. Yukon Gold potatoes peeled and diced into quarters
• 2 large leeks, white and pale green parts only, rinsed well and sliced thin
• 1–1 1/2 cups whole milk
• 1 tablespoon truffle oil
• 4 tablespoons unsalted butter
• 1 tablespoon chives, minced
• Kosher salt and black pepper, to taste