Recipe(tried): Grandma's flat bread

Here is the flat bread recipe we always use:
1 cup warm milk
3/4 cup shortening (or drippings according to the ancient recipe card)
2 tbls sugar
1 tsp salt or seasoned salt
2 packages yeast dissolved in 1/4 cup water
4 cups flour (maybe a little more)

Make the dough into biscuits and let them rise for an hour and a half.
Roll them very thin with scored rolling pin
Sprinkle with seasoned salt if desired [a necessary step in my opinion]
Bake at 425 until light brown and remove from oven