In a separate bowl, mix 2 c warm water, 2 tbsp sugar, and 2½ c all purpose flour.
Put in a glass mason jar. Cover the top with cheesecloth and secure cheesecloth with rubber bands or a mason jar ring.
Keep at room temperature for 5 days. It should be foamy and have a yeasty aroma.
Feeding the starter
Mix ¾ c sugar, 3 tbsp instant potato flakes, and 1 c warm water well. Add to starter.
Let fed starter stand at room temperature all day or overnight (12 hours).
Either reserve 1 c starter for bread or sharing, or refrigerate for 3-5 days. Make bread anytime by allowing 1 cup to reach room temperature.
Feed once a week, whether you make bread or not.
Bread
In a large bowl blend ½ c sugar, ½ c vegetable oil, 1 tbsp salt, 1 c starter, 1½ c warm water, and 6 c plain flour to make a stiff batter. If too sticky add more flour. Optionally, in place of ½ c water use ½ c warm whole milk or cream for sweet rolls.
Grease another bowl, add dough and turn to grease on all sides. Lightly cover and let stand all day or overnight at room temperature.
After letting dough stand or on the next morning, punch down the dough and knead a few times.
Divide dough in half, kneading each part 8-10 times. Place in 2 greased bread pans.
Brush tops with melted margarine. Cover, and let rise in a warm place until doubled in size.
Uncover, and bake at 350 °F for 30-35 minutes until done.
Notes
You can vary this as much as you want, adding more cream and butter for Parker House rolls, roll out into cinnamon rolls, etc.