Mashed Baked Potatoes with Chives

Arrange a rack in lower third of oven; preheat oven to 425°. Scrub 2 lb. russet potatoes and 2 lb. Yukon Gold potatoes and prick all over with a fork. Place on a foil-lined rimmed baking sheet

Halve head of garlic crosswise (as if you’re cutting through the equator) and place on a piece of foil. Drizzle with 1 Tbsp. oil; season with salt and pepper. Fold edges of foil up and over garlic and crimp to close, creating a tight packet. Place on baking sheet with potatoes and roast until a knife slides easily through flesh of potatoes, 65–75 minutes. Let potatoes and garlic cool slightly.

Halve potatoes lengthwise. Using fork, scrape flesh into a large saucepan (include skins if you want to add a little texture). Squeeze garlic cloves from skins into pan. Smash mixture with a potato masher until mostly smooth with only a few lumps.

Cut 6 Tbsp. butter into ½” pieces and combine in a small saucepan with 2 cups half-and-half. Heat over medium-low, swirling, until butter melts and cream is warm but not boiling (it can be simmering gently around the edges).

Pour about half of half-and-half mixture into potato mixture, stirring with a wooden spoon until incorporated and smooth.

If serving mashed potatoes immediately, stir in all of remaining half-and-half mixture and season generously with salt and pepper. If making ahead of time, stir in all but ½ cup of half-and-half mixture, season with salt and pepper, and smooth potatoes to make a flat, even surface. Pour reserved ½ cup half-and-half mixture over and don’t stir (this is to prevent the potatoes from drying out and forming a film). Cover with plastic. You can do this part up to 3 hours ahead.

Thinly slice 8–10 chives.

To serve, warm potatoes over low heat, stirring well with wooden spoon. At this point, if you made it ahead of time, mix in half-and-half mixture floating on top of potatoes.

Transfer mashed potatoes to a platter and top with chives.