Water
Flour
Sugar
Boil berries in a large saucepan, the water should be a couple of inches above the berries. Boil approximately 10 minutes. Strain berry juice and save. Mash the berries to release the juice. Set aside the berries. Mix enough flour and water to make a thick mixture but not a paste. Using the same boiling pan, pour mashed berries and less than half of the saved berry juice back in the pan. Heat at medium-high, slowly pouring the flour mixture in the pan. Keep stirring. If liquid gets thick, pour more berry juice, but not too much. Keep stirring the pudding until it comes to a boil; immediately remove from the stove, there should be some juice left. After the pudding cools, add sugar to taste. Do not leave the pudding cooking, it needs to be kept stirred.