- Place warm water (about 120 F) in a shallow bowl. Sprinkle yeast on top and wait until it becomes foamy (5-10 minutes). 
- In a large bowl, combine 3 ½ cups of the flour, sugar, baking powder, baking soda, salt, parsley, thyme and red pepper. Stir to combine. 
- Using a pastry blender, cut in the butter and shortening until it is the size of small peas. 
- Heat buttermilk until it is lukewarm, about 1 minute in the microwave. 
- Add buttermilk to the proofed yeast and mix to combine. 
- Add the buttermilk combination a little at a time, until you have a soft and elastic dough. 
- Add a little more flour if necessary, if the dough is too wet. The dough should be soft and elastic, but not sticky. 
- Place in a lightly greased bowl and cover with plastic wrap sprayed with non stick spray. Cover with a kitchen towel. 
- Leave to rest in a warm place for about 2 hours, until doubled in size. 
- Preheat oven to 400 F. Spray a 12” cast iron pan with non stick spray. 
- On a lightly floured surface, pat dough to about 1” thick. 
- Fold over twice into a triangle and pat  to 1” thick again. Repeat. 
- Using a 3” biscuit cutter, cut out biscuits using an up and down motion. 
- Transfer to prepared pan with biscuits touching. 
- Repeat and pat and fold procedure with the leftover dough and cut out the remaining biscuits. 
- Cover with a kitchen towel and leave to rest for 15 minutes. 
- Combine melted butter with salt and mix to combine or use salted butter. 
- Brush biscuits with melted butter. 
- Bake for 20-25 minutes, until slightly golden. 
- Brush with melted butter again when you remove them from the oven.