Cream the 1/2 cup of butter and the 1/2 cup of sugar. Add the 3 eggs one a time and mix well between additions.
Add the cooked, mashed sweet potato to the 1/2 cup of buttermilk and whip until smooth. You can use a blender if that’s easier.
Combine the butter mixture with the sweet potato mixture until combined. Add the 2 Tbsp. vanilla and 1/2 cup starter and mix well.
Add the 5-6 cups of flour, 2 teaspoons of salt, and spices.
Don’t add extra flour even if you’re tempted. Mix until all the flour disappears into the wet ingredients.
I usually mix by hand because it’s easier for me to feel rather than time when the dough is all mixed, but you can use a mixer with the dough hook attachment.
Place the dough into a well-oiled or buttered bowl, cover, and allow to culture for 6 hours or overnight.
Allow it to rise as long as it takes to double in size and be poofy.
Your dough is done culturing when it slowly returns a finger indent, though not completely.
When ready, remove the dough from the bowl and roll it out into a rectangle that is 1/8” - 1/4” thick. Make sure it's as even as it can be from one end to the other.
Cut the dough with a pizza cutter or sharp knife in three sections horizontally, to you have three long strips 6” - 8” wide.
Make the filling and spread it evenly over the strips to the edge.