Inspired by the addictive White Castle burger, we set out to re-create the original. Of course, no slider is worth its weight unless it’s on a stellar bun, so we developed one of those too: squishy, slightly sweet, and perfect for sopping up burger juices. If you don’t feel up for a hamburger, you can serve these as dinner rolls, but be sure to plan on more than one per person—they go fast.
What to buy: The shortening and whole milk are critical to the softness of the buns, so don’t try to substitute either.
Game plan: These are best the day they are made but will last up to 3 days when stored covered at room temperature. To revive the buns, give them a pass in the toaster just long enough to warm them through without baking any further.
1Place milk in a small saucepan and bring to a simmer over medium heat. As soon as milk simmers, remove from heat and stir in shortening until melted. Set aside to cool slightly (to about 105°F to 115°F).
2Add warm milk mixture and remaining ingredients to the bowl of a stand mixer fitted with a dough hook attachment. Mix on lowest speed until dough comes away from the sides of the bowl and forms a ball, about 1 minute. Increase speed to medium low and mix until dough is smooth and springy, about 4 minutes.
3Lightly oil a large mixing bowl, add dough, and turn to coat in oil. Cover with a damp towel and let rise in a warm area until doubled in size, about 1 hour.
4Punch down dough and turn onto a clean surface. Divide dough into 18 (1-1/2-ounce) pieces. Shape each piece into a smooth, round bun (keep the rest covered with the towel as you work). To do so, cup your hand around the dough, press down very lightly, and roll the dough against the surface to form a bun. Slightly flatten bun and place on an ungreased baking sheet. Repeat to make 18 buns.
5Set buns aside in a warm area until slightly risen and puffy (note that they will not double in size), about 30 to 40 minutes. Meanwhile, heat the oven to 400°F and arrange the rack in the middle.
6When buns have risen, bake in the oven until they are golden brown, crusty, and have an internal temperature of 190°F, about 15 to 17 minutes. Remove from the oven, transfer to a rack, and let cool at least 10 minutes before serving.