Make Ahead Mashed Potatoes

Ingredients

• 4 to 5 pounds potatoes, peeled and cut into 2-inch chunks
• Salt
• 3 garlic cloves, peeled and whole
• 1 small sprig fresh rosemary
• 3 tablespoons unsalted butter, divided 2 tablespoons and 1 tablespoon
• 8 ounces cream cheese, room temperature
• 1/2 cup plain or greek yogurt, or sour cream
• 1/4 teaspoon fresh minced rosemary
• 2 teaspoons kosher salt
• 1/8 teaspoon freshly ground black pepper
• Chives for garnish

Directions

1. Put the peeled, cut potatoes into a large saucepan and add enough cold water to sit 1 inch above them. Stir 2 teaspoons of salt into the water, then add the garlic cloves and the rosemary sprig. Set the pan over high heat until it reaches a boil, then turn the heat to low, cover the pan, and keep it at a gentle simmer until the potatoes are just tender all the way through, about 10 to 12 minutes.
2. Drain the potatoes as soon as they are ready. Pull out and discard the rosemary sprig, but leave the garlic with the potatoes. While everything is still hot, transfer the potatoes and garlic to a large bowl and mash them roughly with a potato masher or press them through a potato ricer. Using a ricer makes the mash lighter and less gluey.
3. Transfer the riced or roughly mashed potatoes to the bowl of a large upright mixer, or use a sturdy spoon and some muscle. Add 2 tablespoons of butter, the softened cream cheese, and the yogurt. Begin on low, then move up to medium, mixing only until the ingredients come together. Stir in the minced rosemary, the salt, and the pepper. Taste, then adjust with more salt and pepper if needed.
4. Coat the inside of a 2-quart casserole dish generously with butter. Spoon in the mashed potatoes and smooth them into an even layer, then scatter the remaining 1 Tbsp butter over the top. This is the make-ahead point: cover the dish with plastic wrap and refrigerate until you are ready to bake. The potatoes can be prepared up to 2 days ahead, or frozen up to 2 weeks ahead.
5. When it is time to bake, take the dish out of the refrigerator and let it stand for 1 hour so it loses its chill. Heat the oven to 350 degrees F and bake for 30 to 45 minutes, until the surface is lightly browned.