Not sure about your Grandmother, but my Grandma claimed that hers were just cornmeal mixed with water to about the consistency of pancake batter, and then fried in a cast iron skillet.
I will tell you that I've tried it, and most of mine don't come out near as good as I remember hers tasting.
Now my Grandpa used to make a breakfast hoecake that was a skillet-sized biscuit baked on top of the stove. I can't make those at all.
Well, these things were absolutely flat, had a slightly greasy taste, were pure fried, and melted in your mouth. The only other time I have ever seen them was about 25 years ago in a little seafood restauraunt in Mexico Beach, Fla.