To Make Starter: Dissolve yeast in warm water. Add 1 tablespoon white sugar, 1 tablespoon vinegar, 1/2 teaspoon salt, 1 cup of the flour, and 1 cup of the milk in a non-metal bowl and stir with a non-metal spoon until creamy. Cover bowl with plastic wrap and let stand in a warm place for two days to ferment. It will become bubbly and have a sour odor. Do not place in refrigerator. On second day, third day, and fourth day: stir. On fifth day, add 1 cup flour, 1 cup sugar, 1 cup milk, and stir. On sixth, seventh, eighth, and ninth day: stir. On tenth day add 1 cup flour, 1 cup sugar, and 1 cup milk. Reserve 1 cup starter; pour remaining starter, 1 cup each, into 3 containers to give away to friends if desired. Starter is enough for 8 loaves.
To Make Cakes: Preheat oven to 350 degrees F (175 degrees C). Grease two 8 or 9 inch loaf pans.
Mix 1 cup of the starter, oil, baking powder, eggs, 1 cup of the sugar, 2 cups of the flour, 1/4 teaspoon of the salt, vanilla, and chopped nuts. Stir in the baking soda just before pouring the batter into the prepared pans.
Bake at 350 degrees F (175 degrees C) for 45 minutes to 1 hour. Bananas, dates, or raisins can be added for variety.