These sourdough potato rolls are made with a sourdough starter only. After some experimentation, I quite like them that way (and my family agrees!). And unlike some sourdough recipes, you can have them done in one day.
In the bowl of a stand mixer, combine all your ingredients. Use the dough hook attachment (or paddle attachment) and start the mixer on low to gently bring the dough together.
Mix on low speed for approximately 5 to 10 minutes until the dough no longer clings to the sides of the bowl.
If you don't have a stand mixer, you can mix by hand for at least 10 minutes to ensure the gluten bonds fully develop.
Shape your dough into a smooth ball and transfer to a large bowl. Seal it securely with plastic wrap, a plastic bag, aluminum foil, or a lid.
Allow the dough to do its first rise at room temperature for about 8 hours. If you're in a hurry, you can accelerate the sourdough process by placing the bowl in a warm place, though it's unlikely to be ready in less than 6 hours.
When the dough has expanded by at least 75%, the first rise is done. You can even leave it overnight, especially during cooler seasons, but in the warmer summer months, the rise time may be shorter.
Use a bench scraper to divide the dough into 8 equal portions and shape them into dough balls.
You don't have to flour your work surface for this recipe, as the dough would be firm and elastic at this stage.
Arrange the shaped rolls on a baking sheet (sheet pan) or a large baking dish. It's a good idea to place parchment paper underneath or grease the baking dish to prevent the rolls from sticking. Allow them to rise until they're puffy and slightly bigger in size.
The second rise (or final proof) could take anywhere from 2 - 3 hours, depending on the temperature in your kitchen. If you'd like to speed the process up a bit, place the rolls in a warm place.
Bake them in a preheated oven at 375°F (190°C) for 15 - 17 minutes (depending on the strength of your oven), until they are golden brown.
Allow them to cool. Placing them on a wire rack is the best way to cool them. I like to throw a clean towel over them to prevent the crust from becoming too hard.
Notes
If you plan to use these as potato buns for hamburgers, a quick egg wash can make a big difference. Simply whisk together 1 egg and 1 tablespoon of milk (or water) using a pastry brush, then brush it over the rolls just before baking. It'll give them that extra something special.
While it's not a make-or-break rule, consider having all your ingredients at room temperature before you mix them. This little step can help everything blend more smoothly, resulting in a silky dough.
To gauge if the dough is well-mixed, you can use a simple "window pane test": take a piece of dough and gently stretch it out. If it stretches into a thin, translucent membrane that you can see through, the gluten has developed adequately, and it's time to stop the mixing.
Placing the dough in a greased bowl for the first rise can make it less likely to stick. I personally like using olive oil, but you can go with the vegetable oil of your choice.
If the dough sticks to your fingers when you're shaping it, a quick fix is to moisten your hands with warm water.