Step 1: Prepare the Gravy

1. In a large skillet, melt butter over medium heat.
2. Add onion, carrot, and celery, cooking until softened (5-6 minutes).
3. Stir in garlic, salt, pepper, and sage, cooking until fragrant.
4. Sprinkle flour over the mixture, stirring continuously for 2 minutes.
5. Slowly whisk in chicken stock and cream (if using), stirring to prevent lumps.
6. Add shredded chicken and let simmer on low while preparing biscuits.
7. Stir in fresh parsley just before serving.

Step 2: Make the Biscuits

1. Preheat oven to 450°F (232°C).
2. In a large bowl, whisk together flour, baking powder, baking soda, and salt.
3. Cut in cold butter until the mixture resembles coarse crumbs.
4. Pour in cold buttermilk, stirring gently until just combined.
5. Turn dough onto a floured surface and gently fold 2-3 times.
6. Pat to 1-inch thickness and cut out biscuits using a round cutter.
7. Arrange biscuits on a baking sheet and bake for 10-12 minutes until golden brown.

Step 3: Assemble & Serve

1. Split the warm biscuits and ladle hot chicken gravy over them.
2. Garnish with extra parsley and serve immediately.