Preheat the oven to 375°.
In a large mixing bowl, whisk together 4 cups of the flour, salt, sugar, baking soda, and cream of tartar.
Cut in the shortening and butter until the mixture resembles coarse crumbles.
Beat one of the eggs and add it, along with the milk and water, to the flour mixture to form a soft dough.
In another bowl, beat the other egg; then add the brown sugar, and ½ cup flour, mixing well.
Roll the dough into a rectangle shape to ½-inch thickness and spread with the brown sugar mixture.
Beginning with one of the long ends, roll up the dough like a jelly roll and cut into inch-thick slices.
Place the rolls cut side up, about 2 inches apart, on greased baking sheets.
Bake for 8 to 10 minutes or until done.