Make-Ahead Slow Cooker Mashed Potatoes

Step 1
Place potatoes into a large pot, cover with water, and bring to a boil over high heat. Reduce the heat to medium-low and simmer until tender, 20 to 25 minutes. Drain; return potatoes to the pot and stir gently over medium heat until dry, 1 to 2 minutes.

Step 2
Mash potatoes with a hand mixer until smooth. Stir in cream cheese, half-and-half, chives, egg whites, onion powder, salt, and pepper until well blended.

Step 3
Spray a slow cooker insert with nonstick spray and add mashed potatoes. Cut 1/2 cup butter into 8 pieces and scatter over the top of potatoes. Allow potatoes to cool, then cover with lid and store in the refrigerator overnight or until ready to reheat.

Step 4
Remove potatoes from the refrigerator and let them come to room temperature, about 3 1/2 hours.

Step 5
Place a towel under the lid to absorb condensation. Cook on Low, stirring once or twice, 2 1/2 hours. Stir in remaining 1/4 cup butter, 1 tablespoon at a time; then cook for another 30 minutes.