I don't usually keep buttermilk on hand, but Saco buttermilk powder is great for this. Fill up ½ cup of tepid water -- water should feel neither hot nor cold when you stick your finger in it. Add 2 tablespoons of buttermilk powder and stir it into the lukewarm water until it kinda dissolves (there'll still be some lumps...)
Add 2 teaspoons of active dry yeast to the tepid buttermilk. Stir it in to dissolve and let it sit for 5 minutes.
Meanwhile, whisk together the flour, sugar, baking soda, dried parsley, dried thyme, and salt in a large bowl.
Whisk the 2 tablespoons of oil into the buttermilk/yeast mixture.
Add the liquid ingredients to the dry ingredients and stir them around until a dough starts to come together. Knead the dough a few times until it becomes workable - about the consistency of an earlobe. Add more flour if the dough is too loose.
Cover the bowl of dough with plastic wrap and set it aside as you prepare the turkey pot pie filling.