Preheat oven to 450°F.
In a large bowl whisk together the dry ingredients (flour, baking powder, baking soda, salt). In a separate bowl whisk together the wet ingredients (milk, butter, vinegar).
Add the wet ingredients into the dry ingredients and stir until thoroughly combined.
Separate the dough into 6 equal mounds. Drop the dough mounds onto a baking sheet at least 1 inch apart. Bake for 12 to 13 minutes or until lightly browned.
Melt 1 TBSP butter in a saucepan over medium-high heat. Add the mushrooms and cook until well browned and any moisture from the mushrooms has evaporated, about 8 minutes.
Reduce heat to medium and add the remaining 3 TBSP butter to the pan. When the butter melts add the flour and continue to stir until you no longer see white flour, about 1 minute.
Add the sage, thyme, rosemary, red pepper flakes, ½ tsp salt, and ¼ tsp pepper to the pan and stir to combine. Slowly pour in the milk while stirring and bring to a boil.
Reduce heat to low and simmer, stirring often, until gravy is desired thickness. Season with salt and pepper to taste.
Serve gravy over biscuits.
