Sift together the all-purpose flour, whole wheat flour, salt, and baking powder. Cut in the butter into the flour, leaving behind pieces no larger than a pea. Add in the chives and parmesan.
Stir in the buttermilk until everything is just combined - the dough may be a little sticky. Cover and set aside.
In a heavy bottomed sauce pan, melt the 2 tablespoons of butter over medium heat. Add in mushrooms and cook until they are caramelized - about 5 Minutes. Be careful not to stir too much or they won't caramelize. Add in garlic and cook for 1 Minute.
Transfer mushrooms and garlic to your 2 ½ quart baking dish and set aside. Melt one more tablespoon of butter and sauté your onions until they are translucent, about 2 Minutes.
Stirring as needed, add in carrots, celery, turnips, zucchini and fennel and cook until they have begun to caramelize, about 15 Minutes. Transfer to baking dish.
Using the same pan over medium heat, deglaze the hot pan with ¼ cup of the vegetable stock, scraping the bottom of the pan to release the caramelized bits. Reduce until it is mostly gone.
Add in the butter and melt until it is deeply browned. Add in the flour until combined and let cook 1 Minute.
Using a whisk, slowly mix in the remaining vegetable stock until smooth. Mix in pumpkin purée, and cook until mixture begins to thicken, about 2 Minutes.
Add in parmesan cheese and cook 1 Minute until melted. Mix vegetables into the sauce and toss until the vegetables are all coated. Transfer back into the baking dish.
Using a spoon, drop the parmesan chive biscuits on top of the baking dish until all of the biscuit topping is used.
Place the filled and topped baking dish on a sheet pan and place in the oven. Bake for 30 Minutes, or until parmesan chive biscuits are cooked through and browned. Remove and let stand for 10 Minutes before serving.
This recipe uses a deep 2 ½ quart baking dish. If you would like to use a 9x13" pan please double the biscuit recipe.