Turn up the oven to 450 degrees.
While the chicken is cooking, cut the 8 Tbsp. butter into small pieces and place back in the freezer to keep cold.
Chop 1 ½ tsp fresh rosemary and grate ⅓ cup Parmesan.
Mix dry ingredients together in a large bowl: 2 ½ cups flour, 1 TBSP baking powder, ¼ tsp baking soda, 1 tsp salt, 1 ½ tsp. chopped fresh rosemary, and ⅓ cup Parmesan. (The rosemary and Parmesan are optional but are so so good!)
Cut the cold butter into the dough with your fingers or a fork or pastry cutter until butter is in tiny chunks. (I used a pastry cutter in the step-by-step photos)
Mix in the buttermilk and sour cream with a fork until just combined.
Flour your counter or work surface.
Dump the dough out onto your counter or work surface. Gently pat the dough into a small rectangle 1-inch thick.
Using a bench scraper or spatula, fold the dough onto itself three times. Flour underneath the dough in between each fold if needed. This will create flaky layers of dough.
Gently pat the dough into a circle a half-inch thick and cut with a well-floured biscuit cutter.
Place the biscuits onto a parchment-lined baking sheet and brush with buttermilk on the tops and sides.
Bake for 12-15 minutes or until lightly golden brown on top. Keep checking after 10 minutes to prevent over baking.
While the biscuits are baking remove the chicken bones with a small serrated knife.
Mix the honey and dijon mustard together in a small bowl.
Cut the biscuits in half, top with a piece of chicken, add pickles if you like, and drizzle the honey mustard sauce over the chicken.